Merge pull request #2324 from JatinSanghvi/main

fix: Match solution files with exercise files

.cargo/config.toml

@@ -0,0 +1,2 @@
+[alias]
+dev = ["run", "--", "dev"]

.editorconfig

@@ -1,7 +0,0 @@
-root = true
-
-[*.rs]
-end_of_line = lf
-insert_final_newline = true
-indent_style = space
-indent_size = 4

.github/workflows/rust.yml

@@ -1,10 +1,16 @@
-name: Rustlings Tests
+name: Check
 
 on:
   push:
     branches: [main]
+    paths-ignore:
+      - website
+      - '*.md'
   pull_request:
     branches: [main]
+    paths-ignore:
+      - website
+      - '*.md'
 
 env:
   CARGO_TERM_COLOR: always
@@ -14,30 +20,28 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - run: cargo clippy -- --deny warnings
+      - name: Clippy
+        run: cargo clippy -- --deny warnings
   fmt:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: DavidAnson/markdownlint-cli2-action@v16
+      - name: rustfmt
-        with:
+        run: cargo fmt --all --check
-          globs: "exercises/**/*.md"
-      - name: Run cargo fmt
-        run: cargo fmt --all -- --check
   test:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-latest, macOS-latest]
+        os: [ubuntu-latest, windows-latest, macos-latest]
     steps:
       - uses: actions/checkout@v4
       - uses: swatinem/rust-cache@v2
-      - name: Run cargo test
+      - name: cargo test
-        run: cargo test
+        run: cargo test --workspace
   dev-check:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: swatinem/rust-cache@v2
-      - name: Run rustlings dev check
+      - name: rustlings dev check
-        run: cargo run -- dev check --require-solutions
+        run: cargo dev check --require-solutions

.github/workflows/web.yml

@@ -1,87 +0,0 @@
-# Workflow to build your docs with oranda (and mdbook)
-# and deploy them to Github Pages
-name: Web
-
-# We're going to push to the gh-pages branch, so we need that permission
-permissions:
-  contents: write
-
-# What situations do we want to build docs in?
-# All of these work independently and can be removed / commented out
-# if you don't want oranda/mdbook running in that situation
-on:
-  # Check that a PR didn't break docs!
-  #
-  # Note that the "Deploy to Github Pages" step won't run in this mode,
-  # so this won't have any side-effects. But it will tell you if a PR
-  # completely broke oranda/mdbook. Sadly we don't provide previews (yet)!
-  pull_request:
-
-  # Whenever something gets pushed to main, update the docs!
-  # This is great for getting docs changes live without cutting a full release.
-  #
-  # Note that if you're using cargo-dist, this will "race" the Release workflow
-  # that actually builds the Github Release that oranda tries to read (and
-  # this will almost certainly complete first). As a result you will publish
-  # docs for the latest commit but the oranda landing page won't know about
-  # the latest release. The workflow_run trigger below will properly wait for
-  # cargo-dist, and so this half-published state will only last for ~10 minutes.
-  #
-  # If you only want docs to update with releases, disable this, or change it to
-  # a "release" branch. You can, of course, also manually trigger a workflow run
-  # when you want the docs to update.
-  push:
-    branches:
-      - main
-
-  # Whenever a workflow called "Release" completes, update the docs!
-  #
-  # If you're using cargo-dist, this is recommended, as it will ensure that
-  # oranda always sees the latest release right when it's available. Note
-  # however that Github's UI is wonky when you use workflow_run, and won't
-  # show this workflow as part of any commit. You have to go to the "actions"
-  # tab for your repo to see this one running (the gh-pages deploy will also
-  # only show up there).
-  workflow_run:
-    workflows: [ "Release" ]
-    types:
-      - completed
-
-# Alright, let's do it!
-jobs:
-  web:
-    name: Build and deploy site and docs
-    runs-on: ubuntu-latest
-    steps:
-      # Setup
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-      - uses: swatinem/rust-cache@v2
-
-      # If you use any mdbook plugins, here's the place to install them!
-
-      # Install and run oranda (and mdbook)
-      # This will write all output to ./public/ (including copying mdbook's output to there)
-      - name: Install and run oranda
-        run: |
-          curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/oranda/releases/download/v0.3.1/oranda-installer.sh | sh
-          oranda build
-
-      # Deploy to our gh-pages branch (creating it if it doesn't exist)
-      # the "public" dir that oranda made above will become the root dir
-      # of this branch.
-      #
-      # Note that once the gh-pages branch exists, you must
-      # go into repo's settings > pages and set "deploy from branch: gh-pages"
-      # the other defaults work fine.
-      - name: Deploy to Github Pages
-        uses: JamesIves/github-pages-deploy-action@v4.4.1
-        # ONLY if we're on main (so no PRs or feature branches allowed!)
-        if: ${{ github.ref == 'refs/heads/main' }}
-        with:
-          branch: gh-pages
-          # Gotta tell the action where to find oranda's output
-          folder: public
-          token: ${{ secrets.GITHUB_TOKEN }}
-          single-commit: true

.github/workflows/website.yml

@@ -0,0 +1,43 @@
+name: Website
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [main]
+    paths: [website]
+
+jobs:
+  build:
+    defaults:
+      run:
+        working-directory: website
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install TailwindCSS
+        run: npm install
+      - name: Build CSS
+        run: npx @tailwindcss/cli -m -i input.css -o static/main.css
+      - name: Download Zola
+        run: curl -fsSL https://github.com/getzola/zola/releases/download/v0.20.0/zola-v0.20.0-x86_64-unknown-linux-gnu.tar.gz | tar xz
+      - name: Build site
+        run: ./zola build
+      - name: Upload static files as artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: website/public/
+
+  deploy:
+    needs: build
+    # Grant GITHUB_TOKEN the permissions required to make a Pages deployment
+    permissions:
+      pages: write    # to deploy to Pages
+      id-token: write # to verify the deployment originates from an appropriate source
+    # Deploy to the github-pages environment
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Deploy to GitHub Pages
+        uses: actions/deploy-pages@v4

.gitignore

@@ -6,10 +6,6 @@ Cargo.lock
 # State file
 .rustlings-state.txt
 
-# oranda
-public/
-.netlify
-
 # OS
 .DS_Store
 .direnv/

.markdownlint.yml

@@ -1,2 +0,0 @@
-# MD013/line-length Line length, Expected: 80
-MD013: false

.typos.toml

@@ -1,7 +1,7 @@
+[default.extend-words]
+"earch" = "earch" # Because of <s>earch in the list footer
+
 [files]
 extend-exclude = [
   "CHANGELOG.md",
 ]
-
-[default.extend-words]
-"ratatui" = "ratatui"

CHANGELOG.md

@@ -1,10 +1,117 @@
-<a name="6.1.0"></a>
+## Unreleased
+
+### Changed
+
+- `vecs2`: Removed the use of `map` and `collect`, which are only taught later.
+
+## 6.5.0 (2025-08-21)
+
+### Added
+
+- Check that Clippy is installed before initialization
+
+### Changed
+
+- Upgrade to Rust edition 2024
+- Raise the minimum supported Rust version to `1.88`
+- Don't follow symlinks in the file watcher
+- `dev new`: Don't add `.rustlings-state.txt` to `.gitignore`
+
+### Fixed
+
+- Fix file links in VS Code
+- Fix error printing when the progress bar is shown
+- `dev check`: Don't check formatting if there are no solution files
+
+## 6.4.0 (2024-11-11)
+
+### Added
+
+- The list of exercises is now searchable by pressing `s` or `/` 🔍️ (thanks to [@frroossst](https://github.com/frroossst))
+- New option `c` in the prompt to manually check all exercises ✅ (thanks to [@Nahor](https://github.com/Nahor))
+- New command `check-all` to manually check all exercises ✅ (thanks to [@Nahor](https://github.com/Nahor))
+- Addictive animation for showing the progress of checking all exercises. A nice showcase of parallelism in Rust ✨
+- New option `x` in the prompt to reset the file of the current exercise 🔄
+- Allow `dead_code` for all exercises and solutions ⚰️ (thanks to [@huss4in](https://github.com/huss4in))
+- Pause input while running an exercise to avoid unexpected prompt interactions ⏸️
+- Limit the maximum number of exercises to 999. Any community exercises willing to reach that limit? 🔝
+
+### Changed
+
+- `enums3`: Remove redundant enum definition task (thanks to [@senekor](https://github.com/senekor))
+- `if2`: Make the exercise less confusing by avoiding "fizz", "fuzz", "foo", "bar" and "baz" (thanks to [@senekor](https://github.com/senekor))
+- `hashmap3`: Use the method `Entry::or_default`.
+- Update the state of all exercises when checking all of them (thanks to [@Nahor](https://github.com/Nahor))
+- The main prompt doesn't need a confirmation with ENTER on Unix-like systems anymore.
+- No more jumping back to a previous exercise when its file is changed. Use the list to jump between exercises.
+- Dump the solution file after an exercise is done even if the solution's directory doesn't exist.
+- Rework the footer in the list.
+- Optimize the file watcher.
+
+### Fixed
+
+- Fix bad contrast in the list on terminals with a light theme.
+
+## 6.3.0 (2024-08-29)
+
+### Added
+
+- Add the following exercise lints:
+  - `forbid(unsafe_code)`: You shouldn't write unsafe code in Rustlings.
+  - `forbid(unstable_features)`: You don't need unstable features in Rustlings and shouldn't rely on them while learning Rust.
+  - `forbid(todo)`: You forgot a `todo!()`.
+  - `forbid(empty_loop)`: This can only happen by mistake in Rustlings.
+  - `deny(infinite_loop)`: No infinite loops are needed in Rustlings.
+  - `deny(mem_forget)`: You shouldn't leak memory while still learning Rust.
+- Show a link to every exercise file in the list.
+- Add scroll padding in the list.
+- Break the help footer of the list into two lines when the terminal width isn't big enough.
+- Enable scrolling with the mouse in the list.
+- `dev check`: Show the progress of checks.
+- `dev check`: Check that the length of all exercise names is lower than 32.
+- `dev check`: Check if exercise contains no tests and isn't marked with `test = false`.
+
+### Changed
+
+- The compilation time when installing Rustlings is reduced.
+- Pressing `c` in the list for "continue on" now quits the list after setting the selected exercise as the current one.
+- Better highlighting of the solution file after an exercise is done.
+- Don't show the output of successful tests anymore. Instead, show the pretty output for tests.
+- Be explicit about `q` only quitting the list and not the whole program in the list.
+- Be explicit about `r` only resetting one exercise (the selected one) in the list.
+- Ignore the standard output of `git init`.
+- `threads3`: Remove the queue length and improve tests.
+- `errors4`: Use match instead of a comparison chain in the solution.
+- `functions3`: Only take `u8` to avoid using a too high number of iterations by mistake.
+- `dev check`: Always check with strict Clippy (warnings to errors) when checking the solutions.
+
+### Fixed
+
+- Fix the error on some systems about too many open files during the final check of all exercises.
+- Fix the list when the terminal height is too low.
+- Restore the terminal after an error in the list.
+
+## 6.2.0 (2024-08-09)
+
+### Added
+
+- Show a message before checking and running an exercise. This gives the user instant feedback and avoids confusion if the checks take too long.
+- Show a helpful error message when trying to install Rustlings with a Rust version lower than the minimum one that Rustlings supports.
+- Add a `README.md` file to the `solutions/` directory.
+- Allow initializing Rustlings in a Cargo workspace.
+- `dev check`: Check that all solutions are formatted with `rustfmt`.
+
+### Changed
+
+- Remove the state file and the solutions directory from the generated `.gitignore` file.
+- Run the final check of all exercises in parallel.
+- Small exercise improvements.
 
 ## 6.1.0 (2024-07-10)
 
 #### Added
 
-- `dev check`: Check that all exercises (including third-party ones) include at least one `TODO` comment.
+- `dev check`: Check that all exercises (including community ones) include at least one `TODO` comment.
 - `dev check`: Check that all exercises actually fail to run (not already solved).
 
 #### Changed
@@ -17,15 +124,11 @@
 - Exit with a helpful error message on missing/unsupported terminal/TTY.
 - Mark the last exercise as done.
 
-<a name="6.0.1"></a>
-
 ## 6.0.1 (2024-07-04)
 
 Small exercise improvements and fixes.
 Most importantly, fixed that the exercise `clippy1` was already solved 😅
 
-<a name="6.0.0"></a>
-
 ## 6.0.0 (2024-07-03)
 
 This release is the result of a complete rewrite to deliver a ton of new features and improvements ✨
@@ -54,7 +157,7 @@ You can read about the motivations of this change in [this issue](https://github
 
 ### List mode
 
-A list mode was added using [Ratatui](https://ratatui.rs).
+A new list mode was added!
 You can enter it by entering `l` in the watch mode.
 It offers the following features:
 
@@ -83,15 +186,13 @@ This should avoid issues related to the language server or to running exercises,
 Clippy lints are now shown on all exercises, not only the Clippy exercises 📎
 Make Clippy your friend from early on 🥰
 
-### Third-party exercises
+### Community Exercises
 
-Rustlings now supports third-party exercises!
+Rustlings now supports community exercises!
 
 Do you want to create your own set of Rustlings exercises to focus on some specific topic?
 Or do you want to translate the original Rustlings exercises?
-Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXERCISES.md)!
+Then follow the link to the guide about [community exercises](https://rustlings.rust-lang.org/community-exercises)!
-
-<a name="5.6.1"></a>
 
 ## 5.6.1 (2023-09-18)
 
@@ -108,8 +209,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - `as_ref_mut`: Fixed a typo in a test function name.
 - `enums3`: Fixed formatting with `rustfmt`.
 
-<a name="5.6.0"></a>
-
 ## 5.6.0 (2023-09-04)
 
 #### Added
@@ -149,16 +248,12 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Lots of Nix housekeeping that I don't feel qualified to write about!
 - Improved CI workflows, we're now testing on multiple platforms at once.
 
-<a name="5.5.1"></a>
-
 ## 5.5.1 (2023-05-17)
 
 #### Fixed
 
 - Reverted `rust-project.json` path generation due to an upstream `rust-analyzer` fix.
 
-<a name="5.5.0"></a>
-
 ## 5.5.0 (2023-05-17)
 
 #### Added
@@ -193,8 +288,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Added a markdown linter to run on GitHub actions
 - Split quick installation section into two code blocks
 
-<a name="5.4.1"></a>
-
 ## 5.4.1 (2023-03-10)
 
 #### Changed
@@ -210,8 +303,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - `macros4`: Prevented auto-fix by adding `#[rustfmt::skip]`
 - `cli`: Actually show correct progress percentages
 
-<a name="5.4.0"></a>
-
 ## 5.4.0 (2023-02-12)
 
 #### Changed
@@ -240,8 +331,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 
 - Bumped min Rust version to 1.58 in installation script
 
-<a name="5.3.0"></a>
-
 ## 5.3.0 (2022-12-23)
 
 #### Added
@@ -274,8 +363,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Applied some Clippy and rustfmt formatting
 - Added a note on Windows PowerShell and other shell compatibility
 
-<a name="5.2.1"></a>
-
 ## 5.2.1 (2022-09-06)
 
 #### Fixed
@@ -289,8 +376,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 
 - Fixed a typo in README.md
 
-<a name="5.2.0"></a>
-
 ## 5.2.0 (2022-08-27)
 
 #### Added
@@ -307,16 +392,12 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **quiz1**: Adjusted the explanations to be consistent with
   the tests
 
-<a name="5.1.1"></a>
-
 ## 5.1.1 (2022-08-17)
 
 #### Bug Fixes
 
 - Fixed an incorrect assertion in options1
 
-<a name="5.1.0"></a>
-
 ## 5.1.0 (2022-08-16)
 
 #### Features
@@ -351,8 +432,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Clarified manual installation instructions using `cargo install --path .`
 - Added a link to our Zulip in the readme file
 
-<a name="5.0.0"></a>
-
 ## 5.0.0 (2022-07-16)
 
 #### Features
@@ -425,8 +504,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Updated spacing in Cargo.toml.
 - Added a GitHub actions config so that tests run on every PR/commit.
 
-<a name="4.8.0"></a>
-
 ## 4.8.0 (2022-07-01)
 
 #### Features
@@ -447,8 +524,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Replaced the git.io URL with the fully qualified URL because of git.io's sunsetting.
 - Removed the deprecated Rust GitPod extension.
 
-<a name="4.7.1"></a>
-
 ## 4.7.1 (2022-04-20)
 
 #### Features
@@ -469,8 +544,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - The changelog will now be manually written instead of being automatically generated by the
   Git log.
 
-<a name="4.7.0"></a>
-
 ## 4.7.0 (2022-04-14)
 
 #### Features
@@ -511,8 +584,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Add hints on how to get GCC installed (#741) ([bc56861](https://github.com/rust-lang/rustlings/commit/bc5686174463ad6f4f6b824b0e9b97c3039d4886))
 - Fix some code blocks that were not highlighted ([17f9d74](https://github.com/rust-lang/rustlings/commit/17f9d7429ccd133a72e815fb5618e0ce79560929))
 
-<a name="4.6.0"></a>
-
 ## 4.6.0 (2021-09-25)
 
 #### Features
@@ -535,8 +606,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
   - Clarify instructions ([df25684c](https://github.com/rust-lang/rustlings/commit/df25684cb79f8413915e00b5efef29369849cef1))
 - **quiz1:** Fix inconsistent wording (#826) ([03131a3d](https://github.com/rust-lang/rustlings/commit/03131a3d35d9842598150f9da817f7cc26e2669a))
 
-<a name="4.5.0"></a>
-
 ## 4.5.0 (2021-07-07)
 
 #### Features
@@ -557,8 +626,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **try_from_into, from_str:** hints for dyn Error ([11d2cf0d](https://github.com/rust-lang/rustlings/commit/11d2cf0d604dee3f5023c17802d69438e69fa50e))
 - **variables5:** confine the answer further ([48ffcbd2](https://github.com/rust-lang/rustlings/commit/48ffcbd2c4cc4d936c2c7480019190f179813cc5))
 
-<a name="4.4.0"></a>
-
 ## 4.4.0 (2021-04-24)
 
 #### Bug Fixes
@@ -600,8 +667,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
   - updated progress percentage ([1c6f7e4b](https://github.com/rust-lang/rustlings/commit/1c6f7e4b7b9b3bd36f4da2bb2b69c549cc8bd913))
   - added progress info ([c0e3daac](https://github.com/rust-lang/rustlings/commit/c0e3daacaf6850811df5bc57fa43e0f249d5cfa4))
 
-<a name="4.3.0"></a>
-
 ## 4.3.0 (2020-12-29)
 
 #### Features
@@ -624,8 +689,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
   - Update description (#584) ([96347df9](https://github.com/rust-lang/rustlings/commit/96347df9df294f01153b29d9ad4ba361f665c755))
 - **vec1:** Have test compare every element in a and v ([9b6c6293](https://github.com/rust-lang/rustlings/commit/9b6c629397b24b944f484f5b2bbd8144266b5695))
 
-<a name="4.2.0"></a>
-
 ## 4.2.0 (2020-11-07)
 
 #### Features
@@ -646,8 +709,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
   - missing comma in test ([4fb230da](https://github.com/rust-lang/rustlings/commit/4fb230daf1251444fcf29e085cee222a91f8a37e))
 - **quiz3:** Second test is for odd numbers, not even. (#553) ([18e0bfef](https://github.com/rust-lang/rustlings/commit/18e0bfef1de53071e353ba1ec5837002ff7290e6))
 
-<a name="4.1.0"></a>
-
 ## 4.1.0 (2020-10-05)
 
 #### Bug Fixes
@@ -670,8 +731,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **cli:** Added 'cls' command to 'watch' mode (#474) ([4f2468e1](https://github.com/rust-lang/rustlings/commit/4f2468e14f574a93a2e9b688367b5752ed96ae7b))
 - **try_from_into:** Add insufficient length test (#469) ([523d18b8](https://github.com/rust-lang/rustlings/commit/523d18b873a319f7c09262f44bd40e2fab1830e5))
 
-<a name="4.0.0"></a>
-
 ## 4.0.0 (2020-07-08)
 
 #### Breaking Changes
@@ -713,8 +772,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **test2:** name of type String and &str (#394) ([d6c0a688](https://github.com/rust-lang/rustlings/commit/d6c0a688e6a96f93ad60d540d4b326f342fc0d45))
 - **variables6:** minor typo (#419) ([524e17df](https://github.com/rust-lang/rustlings/commit/524e17df10db95f7b90a0f75cc8997182a8a4094))
 
-<a name="3.0.0"></a>
-
 ## 3.0.0 (2020-04-11)
 
 #### Breaking Changes
@@ -737,8 +794,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - add new exercises for generics (#280) ([76be5e4e](https://github.com/rust-lang/rustlings/commit/76be5e4e991160f5fd9093f03ee2ba260e8f7229))
 - **ci:** add buildkite config ([b049fa2c](https://github.com/rust-lang/rustlings/commit/b049fa2c84dba0f0c8906ac44e28fd45fba51a71))
 
-<a name="2.2.1"></a>
-
 ### 2.2.1 (2020-02-27)
 
 #### Bug Fixes
@@ -749,13 +804,11 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 
 - Add clippy lints (#269) ([1e2fd9c9](https://github.com/rust-lang/rustlings/commit/1e2fd9c92f8cd6e389525ca1a999fca4c90b5921))
 
-<a name="2.2.0"></a>
-
 ## 2.2.0 (2020-02-25)
 
 #### Bug Fixes
 
-- Update deps to version compatable with aarch64-pc-windows (#263) ([19a93428](https://github.com/rust-lang/rustlings/commit/19a93428b3c73d994292671f829bdc8e5b7b3401))
+- Update deps to version compatible with aarch64-pc-windows (#263) ([19a93428](https://github.com/rust-lang/rustlings/commit/19a93428b3c73d994292671f829bdc8e5b7b3401))
 - **docs:**
   - Added a necessary step to Windows installation process (#242) ([3906efcd](https://github.com/rust-lang/rustlings/commit/3906efcd52a004047b460ed548037093de3f523f))
   - Fixed mangled sentence from book; edited for clarity (#266) ([ade52ff](https://github.com/rust-lang/rustlings/commit/ade52ffb739987287ddd5705944c8777705faed9))
@@ -778,8 +831,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Added traits exercises (#274 but specifically #216, which originally added
   this :heart:) ([b559cdd](https://github.com/rust-lang/rustlings/commit/b559cdd73f32c0d0cfc1feda39f82b3e3583df17))
 
-<a name="2.1.0"></a>
-
 ## 2.1.0 (2019-11-27)
 
 #### Bug Fixes
@@ -797,8 +848,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 
 - **watch:** show hint while watching ([8143d57b](https://github.com/rust-lang/rustlings/commit/8143d57b4e88c51341dd4a18a14c536042cc009c))
 
-<a name="2.0.0"></a>
-
 ## 2.0.0 (2019-11-12)
 
 #### Bug Fixes
@@ -819,8 +868,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **cli:** check for rustc before doing anything ([36a033b8](https://github.com/rust-lang/rustlings/commit/36a033b87a6549c1e5639c908bf7381c84f4f425))
 - **hint:** Add test for hint ([ce9fa6eb](https://github.com/rust-lang/rustlings/commit/ce9fa6ebbfdc3e7585d488d9409797285708316f))
 
-<a name="1.5.1"></a>
-
 ### 1.5.1 (2019-11-11)
 
 #### Bug Fixes
@@ -832,8 +879,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **threads:** Move Threads behind SLT ([fbe91a67](https://github.com/rust-lang/rustlings/commit/fbe91a67a482bfe64cbcdd58d06ba830a0f39da3), closes [#205](https://github.com/rust-lang/rustlings/issues/205))
 - **watch:** clear screen before each `verify()` ([3aff590](https://github.com/rust-lang/rustlings/commit/3aff59085586c24196a547c2693adbdcf4432648))
 
-<a name="1.5.0"></a>
-
 ## 1.5.0 (2019-11-09)
 
 #### Bug Fixes
@@ -858,8 +903,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Added exercise for struct update syntax ([1c4c8764](https://github.com/rust-lang/rustlings/commit/1c4c8764ed118740cd4cee73272ddc6cceb9d959))
 - **iterators2:** adds iterators2 exercise including config ([9288fccf](https://github.com/rust-lang/rustlings/commit/9288fccf07a2c5043b76d0fd6491e4cf72d76031))
 
-<a name="1.4.1"></a>
-
 ### 1.4.1 (2019-08-13)
 
 #### Bug Fixes
@@ -868,8 +911,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **option1:** Add test for prematurely passing exercise ([a750e4a1](https://github.com/rust-lang/rustlings/commit/a750e4a1a3006227292bb17d57d78ce84da6bfc6))
 - **test1:** Swap assertion parameter order ([4086d463](https://github.com/rust-lang/rustlings/commit/4086d463a981e81d97781851d17db2ced290f446))
 
-<a name="1.4.0"></a>
-
 ## 1.4.0 (2019-07-13)
 
 #### Bug Fixes
@@ -886,8 +927,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - **changelog:** Use clog for changelogs ([34e31232](https://github.com/rust-lang/rustlings/commit/34e31232dfddde284a341c9609b33cd27d9d5724))
 - **iterators2:** adds iterators2 exercise including config ([9288fccf](https://github.com/rust-lang/rustlings/commit/9288fccf07a2c5043b76d0fd6491e4cf72d76031))
 
-<a name="1.3.0"></a>
-
 ### 1.3.0 (2019-06-05)
 
 #### Features
@@ -903,16 +942,12 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Fix broken link (#164, @HanKruiger)
 - Remove highlighting and syntect (#167, @komaeda)
 
-<a name="1.2.2"></a>
-
 ### 1.2.2 (2019-05-07)
 
 #### Bug Fixes
 
 - Reverted `--nocapture` flag since it was causing tests to pass unconditionally
 
-<a name="1.2.1"></a>
-
 ### 1.2.1 (2019-04-22)
 
 #### Bug Fixes
@@ -920,8 +955,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Fix the `--nocapture` feature (@komaeda)
 - Provide a nicer error message for when you're in the wrong directory
 
-<a name="1.2.0"></a>
-
 ### 1.2.0 (2019-04-22)
 
 #### Features
@@ -929,8 +962,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Add errors to exercises that compile without user changes (@yvan-sraka)
 - Use --nocapture when testing, enabling `println!` when running (@komaeda)
 
-<a name="1.1.1"></a>
-
 ### 1.1.1 (2019-04-14)
 
 #### Bug fixes
@@ -943,8 +974,6 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Fix links by deleting book version (@diodfr, #142)
 - Canonicalize paths to fix path matching (@cjpearce, #143)
 
-<a name="1.1.0"></a>
-
 ### 1.1.0 (2019-03-20)
 
 - errors2.rs: update link to Rust book (#124)
@@ -954,16 +983,12 @@ Then follow the link to the guide about [third-party exercises](THIRD_PARTY_EXER
 - Give a warning when Rustlings isn't run from the right directory (#123)
 - Verify that rust version is recent enough to install Rustlings (#131)
 
-<a name="1.0.1"></a>
-
 ### 1.0.1 (2019-03-06)
 
 - Adds a way to install Rustlings in one command (`curl -L https://git.io/rustlings | bash`)
 - Makes `rustlings watch` react to create file events (@shaunbennett, #117)
 - Reworks the exercise management to use an external TOML file instead of just listing them in the code
 
-<a name="1.0.0"></a>
-
 ### 1.0.0 (2019-03-06)
 
 Initial release.

Cargo.toml

@@ -1,27 +1,25 @@
 [workspace]
-resolver = "2"
 exclude = [
-  "tests/fixture/failure",
+  "tests/test_exercises",
-  "tests/fixture/state",
-  "tests/fixture/success",
   "dev",
 ]
 
 [workspace.package]
-version = "6.1.0"
+version = "6.5.0"
 authors = [
-  "Liv <mokou@fastmail.com>",
+  "Mo Bitar <mo8it@proton.me>", # https://github.com/mo8it
-  "Mo Bitar <mo8it@proton.me>",
+  "Liv <mokou@fastmail.com>", # https://github.com/shadows-withal
   # Alumni
-  "Carol (Nichols || Goulding) <carol.nichols@gmail.com>",
+  "Carol (Nichols || Goulding) <carol.nichols@gmail.com>", # https://github.com/carols10cents
 ]
 repository = "https://github.com/rust-lang/rustlings"
 license = "MIT"
-edition = "2021"
+edition = "2024" # On Update: Update the edition of `rustfmt` in `dev check` and `CARGO_TOML` in `dev new`.
+rust-version = "1.88"
 
 [workspace.dependencies]
-serde = { version = "1.0.204", features = ["derive"] }
+serde = { version = "1.0", features = ["derive"] }
-toml_edit = { version = "0.22.15", default-features = false, features = ["parse", "serde"] }
+toml = { version = "0.9", default-features = false, features = ["std", "parse", "serde"] }
 
 [package]
 name = "rustlings"
@@ -31,6 +29,7 @@ authors.workspace = true
 repository.workspace = true
 license.workspace = true
 edition.workspace = true
+rust-version.workspace = true
 keywords = [
   "exercise",
   "learning",
@@ -46,21 +45,20 @@ include = [
 ]
 
 [dependencies]
-anyhow = "1.0.86"
+anyhow = "1.0"
-clap = { version = "4.5.9", features = ["derive"] }
+clap = { version = "4.5", features = ["derive"] }
-crossterm = "0.27.0"
+crossterm = { version = "0.29", default-features = false, features = ["windows", "events"] }
-hashbrown = "0.14.5"
+notify = "8.0"
-notify-debouncer-mini = { version = "0.4.1", default-features = false }
+rustlings-macros = { path = "rustlings-macros", version = "=6.5.0" }
-os_pipe = "1.2.0"
+serde_json = "1.0"
-ratatui = { version = "0.27.0", default-features = false, features = ["crossterm"] }
-rustlings-macros = { path = "rustlings-macros", version = "=6.1.0" }
-serde_json = "1.0.120"
 serde.workspace = true
-toml_edit.workspace = true
+toml.workspace = true
+
+[target.'cfg(not(windows))'.dependencies]
+rustix = { version = "1.0", default-features = false, features = ["std", "stdio", "termios"] }
 
 [dev-dependencies]
-assert_cmd = "2.0.14"
+tempfile = "3.21"
-predicates = "3.1.0"
 
 [profile.release]
 panic = "abort"
@@ -70,3 +68,20 @@ panic = "abort"
 
 [package.metadata.release]
 pre-release-hook = ["./release-hook.sh"]
+pre-release-commit-message = "Release 🎉"
+
+[workspace.lints.rust]
+unsafe_code = "forbid"
+unstable_features = "forbid"
+
+[workspace.lints.clippy]
+empty_loop = "forbid"
+disallowed-types = "deny"
+disallowed-methods = "deny"
+infinite_loop = "deny"
+mem_forget = "deny"
+dbg_macro = "warn"
+todo = "warn"
+
+[lints]
+workspace = true

README.md

@@ -1,143 +1,7 @@
-<div class="oranda-hide">
+# [Rustlings](https://rustlings.rust-lang.org) 🦀
 
-# Rustlings 🦀❤️
+Small exercises to get you used to reading and writing [Rust](https://www.rust-lang.org) code - _Recommended in parallel to reading [the official Rust book](https://doc.rust-lang.org/book) 📚️_
 
-</div>
+Visit the **website** for a demo, info about setup and more:
 
-Greetings and welcome to Rustlings.
+## ➡️ [rustlings.rust-lang.org](https://rustlings.rust-lang.org) ⬅️
-This project contains small exercises to get you used to reading and writing Rust code.
-This includes reading and responding to compiler messages!
-
-It is recommended to do the Rustlings exercises in parallel to reading [the official Rust book](https://doc.rust-lang.org/book/), the most comprehensive resource for learning Rust 📚️
-
-[Rust By Example](https://doc.rust-lang.org/rust-by-example/) is another recommended resource that you might find helpful.
-It contains code examples and exercises similar to Rustlings, but online.
-
-## Getting Started
-
-### Installing Rust
-
-Before installing Rustlings, you need to have _Rust installed_.
-Visit [www.rust-lang.org/tools/install](https://www.rust-lang.org/tools/install) for further instructions on installing Rust.
-This will also install _Cargo_, Rust's package/project manager.
-
-> 🐧 If you're on Linux, make sure you've installed `gcc` (for a linker).
->
-> Deb: `sudo apt install gcc`.
-> Dnf: `sudo dnf install gcc`.
-
-> 🍎 If you're on MacOS, make sure you've installed Xcode and its developer tools by running `xcode-select --install`.
-
-### Installing Rustlings
-
-The following command will download and compile Rustlings:
-
-```bash
-cargo install rustlings
-```
-
-<details>
-<summary><strong>If the installation fails…</strong> (<em>click to expand</em>)</summary>
-
-- Make sure you have the latest Rust version by running `rustup update`
-- Try adding the `--locked` flag: `cargo install rustlings --locked`
-- Otherwise, please [report the issue](https://github.com/rust-lang/rustlings/issues/new)
-
-</details>
-
-### Initialization
-
-After installing Rustlings, run the following command to initialize the `rustlings/` directory:
-
-```bash
-rustlings init
-```
-
-Now, go into the newly initialized directory and launch Rustlings for further instructions on getting started with the exercises:
-
-```bash
-cd rustlings/
-rustlings
-```
-
-## Working environment
-
-### Editor
-
-Our general recommendation is [VS Code](https://code.visualstudio.com/) with the [rust-analyzer plugin](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust-analyzer).
-But any editor that supports [rust-analyzer](https://rust-analyzer.github.io/) should be enough for working on the exercises.
-
-### Terminal
-
-While working with Rustlings, please use a modern terminal for the best user experience.
-The default terminal on Linux and Mac should be sufficient.
-On Windows, we recommend the [Windows Terminal](https://aka.ms/terminal).
-
-If you use VS Code, the builtin terminal should also be fine.
-
-## Doing exercises
-
-The exercises are sorted by topic and can be found in the subdirectory `exercises/<topic>`.
-For every topic, there is an additional `README.md` file with some resources to get you started on the topic.
-We highly recommend that you have a look at them before you start 📚️
-
-Most exercises contain an error that keeps them from compiling, and it's up to you to fix it!
-Some exercises contain tests that need to pass for the exercise to be done ✅
-
-Search for `TODO` and `todo!()` to find out what you need to change.
-Ask for hints by entering `h` in the _watch mode_ 💡
-
-### Watch Mode
-
-After [initialization](#initialization), Rustlings can be launched by simply running the command `rustlings`.
-
-This will start the _watch mode_ which walks you through the exercises in a predefined order (what we think is best for newcomers).
-It will rerun the current exercise automatically every time you change the exercise's file in the `exercises/` directory.
-
-<details>
-<summary><strong>If detecting file changes in the <code>exercises/</code> directory fails…</strong> (<em>click to expand</em>)</summary>
-
-> You can add the **`--manual-run`** flag (`rustlings --manual-run`) to manually rerun the current exercise by entering `r` in the watch mode.
->
-> Please [report the issue](https://github.com/rust-lang/rustlings/issues/new) with some information about your operating system and whether you run Rustlings in a container or virtual machine (e.g. WSL).
-
-</details>
-
-### Exercise List
-
-In the [watch mode](#watch-mode) (after launching `rustlings`), you can enter `l` to open the interactive exercise list.
-
-The list allows you to…
-
-- See the status of all exercises (done or pending)
-- `c`: Continue at another exercise (temporarily skip some exercises or go back to a previous one)
-- `r`: Reset status and file of an exercise (you need to _reload/reopen_ its file in your editor afterwards)
-
-See the footer of the list for all possible keys.
-
-## Continuing On
-
-Once you've completed Rustlings, put your new knowledge to good use!
-Continue practicing your Rust skills by building your own projects, contributing to Rustlings, or finding other open-source projects to contribute to.
-
-## Third-Party Exercises
-
-Do you want to create your own set of Rustlings exercises to focus on some specific topic?
-Or do you want to translate the original Rustlings exercises?
-Then follow the link to the guide about [third-party exercises](https://github.com/rust-lang/rustlings/blob/main/THIRD_PARTY_EXERCISES.md)!
-
-## Uninstalling Rustlings
-
-If you want to remove Rustlings from your system, run the following command:
-
-```bash
-cargo uninstall rustlings
-```
-
-## Contributing
-
-See [CONTRIBUTING.md](https://github.com/rust-lang/rustlings/blob/main/CONTRIBUTING.md) 🔗
-
-## Contributors ✨
-
-Thanks to [all the wonderful contributors](https://github.com/rust-lang/rustlings/graphs/contributors) 🎉

THIRD_PARTY_EXERCISES.md

@@ -1,53 +0,0 @@
-# Third-Party Exercises
-
-The support of Rustlings for third-party exercises allows you to create your own set of Rustlings exercises to focus on some specific topic.
-You could also offer a translation of the original Rustlings exercises as third-party exercises.
-
-## Getting started
-
-To create third-party exercises, install Rustlings and run `rustlings dev new PROJECT_NAME`.
-This command will, similar to `cargo new PROJECT_NAME`, create a template directory called `PROJECT_NAME` with all what you need to get started.
-
-Read the comments in the generated `info.toml` file to understand its format.
-It allows you to set a custom welcome and final message and specify the metadata of every exercise.
-
-## Create an exercise
-
-Here is an example of the metadata of one file:
-
-```toml
-[[exercises]]
-name = "intro1"
-hint = """
-To finish this exercise, you need to …
-This link might help you …"""
-```
-
-After entering this in `info.toml`, create the file `intro1.rs` in the `exercises/` directory.
-The exercise needs to contain a `main` function, but it can be empty.
-Adding tests is recommended.
-Look at the official Rustlings exercises for inspiration.
-
-You can optionally add a solution file `intro1.rs` to the `solutions/` directory.
-
-Now, run `rustlings dev check`.
-It will tell you about any issues with your exercises.
-For example, it will tell you to run `rustlings dev update` to update the `Cargo.toml` file to include the new exercise `intro1`.
-
-`rustlings dev check` will also run your solutions (if you have any) to make sure that they run successfully.
-
-That's it!
-You finished your first exercise 🎉
-
-## Publish
-
-Now, add more exercises and publish them as a Git repository.
-
-Users just have to clone that repository and run `rustlings` in it to start working on your set of exercises just like the official ones.
-
-One difference to the official exercises is that the solution files will not be hidden until the user finishes an exercise.
-But you can trust the users to not look at the solution too early 😉
-
-## Share
-
-After publishing your set of exercises, open an issue or a pull request in the official Rustlings repository to link to your project in the README 😃

build.rs

@@ -0,0 +1,5 @@
+fn main() {
+    // Fix building from source on Windows because it can't handle file links.
+    #[cfg(windows)]
+    let _ = std::fs::copy("dev/Cargo.toml", "dev-Cargo.toml");
+}

clippy.toml

@@ -0,0 +1,11 @@
+disallowed-types = [
+  { path = "crossterm::style::Stylize", reason = "inefficient, use `.queue(…)` instead" },
+  { path = "crossterm::style::styled_content::StyledContent", reason = "inefficient, use `.queue(…)` instead" },
+]
+
+disallowed-methods = [
+  { path = "crossterm::style::style", reason = "inefficient, use `.queue(…)` instead" },
+  { path = "std::thread::spawn", replacement = "std::thread::Builder::spawn", reason = "handle the error" },
+  { path = "std::thread::Scope::spawn", replacement = "std::thread::Builder::spawn", reason = "handle the error" },
+  { path = "std::process::exit", replacement = "std::process::ExitCode" },
+]

dev/Cargo.toml

@@ -1,4 +1,4 @@
-# Don't edit the `bin` list manually! It is updated by `cargo run -- dev update`. This comment line will be stripped in `rustlings init`.
+# Don't edit the `bin` list manually! It is updated by `cargo dev update`. This comment line will be stripped in `rustlings init`.
 bin = [
   { name = "intro1", path = "../exercises/00_intro/intro1.rs" },
   { name = "intro1_sol", path = "../solutions/00_intro/intro1.rs" },
@@ -192,6 +192,32 @@ bin = [
 
 [package]
 name = "exercises"
-edition = "2021"
+edition = "2024"
 # Don't publish the exercises on crates.io!
 publish = false
+
+[profile.release]
+panic = "abort"
+
+[profile.dev]
+panic = "abort"
+
+[lints.rust]
+# You shouldn't write unsafe code in Rustlings!
+unsafe_code = "forbid"
+# You don't need unstable features in Rustlings and shouldn't rely on them while learning Rust.
+unstable_features = "forbid"
+# Dead code warnings can't be avoided in some exercises and might distract while learning.
+dead_code = "allow"
+
+[lints.clippy]
+# You forgot a `todo!()`!
+todo = "forbid"
+# This can only happen by mistake in Rustlings.
+empty_loop = "forbid"
+# No infinite loops are needed in Rustlings.
+infinite_loop = "deny"
+# You shouldn't leak memory while still learning Rust!
+mem_forget = "deny"
+# Currently, there are no disallowed methods. This line avoids problems when developing Rustlings.
+disallowed_methods = "allow"

exercises/00_intro/intro1.rs

@@ -1,4 +1,4 @@
-// TODO: We sometimes encourage you to keep trying things on a given exercise,
+// TODO: We sometimes encourage you to keep trying things on a given exercise
 // even after you already figured it out. If you got everything working and feel
 // ready for the next exercise, enter `n` in the terminal.
 //
@@ -6,8 +6,7 @@
 // Try adding a new `println!` and check the updated output in the terminal.
 
 fn main() {
-    println!("Hello and");
+    println!(r#"       Welcome to...                      "#);
-    println!(r#"       welcome to...                      "#);
     println!(r#"                 _   _ _                  "#);
     println!(r#"  _ __ _   _ ___| |_| (_)_ __   __ _ ___  "#);
     println!(r#" | '__| | | / __| __| | | '_ \ / _` / __| "#);

exercises/01_variables/README.md

@@ -1,7 +1,7 @@
 # Variables
 
 In Rust, variables are immutable by default.
-When a variable is immutable, once a value is bound to a name, you can’t change that value.
+When a variable is immutable, once a value is bound to a name, you can't change that value.
 You can make them mutable by adding `mut` in front of the variable name.
 
 ## Further information

exercises/01_variables/variables1.rs

@@ -1,5 +1,5 @@
 fn main() {
-    // TODO: Add missing keyword.
+    // TODO: Add the missing keyword.
     x = 5;
 
     println!("x has the value {x}");

exercises/01_variables/variables5.rs

@@ -1,6 +1,6 @@
 fn main() {
     let number = "T-H-R-E-E"; // Don't change this line
-    println!("Spell a number: {}", number);
+    println!("Spell a number: {number}");
 
     // TODO: Fix the compiler error by changing the line below without renaming the variable.
     number = 3;

exercises/02_functions/functions3.rs

@@ -1,4 +1,4 @@
-fn call_me(num: u32) {
+fn call_me(num: u8) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

exercises/03_if/if2.rs

@@ -1,7 +1,7 @@
 // TODO: Fix the compiler error on this function.
-fn foo_if_fizz(fizzish: &str) -> &str {
+fn picky_eater(food: &str) -> &str {
-    if fizzish == "fizz" {
+    if food == "strawberry" {
-        "foo"
+        "Yummy!"
     } else {
         1
     }
@@ -18,18 +18,20 @@ mod tests {
     use super::*;
 
     #[test]
-    fn foo_for_fizz() {
+    fn yummy_food() {
-        // This means that calling `foo_if_fizz` with the argument "fizz" should return "foo".
+        // This means that calling `picky_eater` with the argument "strawberry" should return "Yummy!".
-        assert_eq!(foo_if_fizz("fizz"), "foo");
+        assert_eq!(picky_eater("strawberry"), "Yummy!");
     }
 
     #[test]
-    fn bar_for_fuzz() {
+    fn neutral_food() {
-        assert_eq!(foo_if_fizz("fuzz"), "bar");
+        assert_eq!(picky_eater("potato"), "I guess I can eat that.");
     }
 
     #[test]
-    fn default_to_baz() {
+    fn default_disliked_food() {
-        assert_eq!(foo_if_fizz("literally anything"), "baz");
+        assert_eq!(picky_eater("broccoli"), "No thanks!");
+        assert_eq!(picky_eater("gummy bears"), "No thanks!");
+        assert_eq!(picky_eater("literally anything"), "No thanks!");
     }
 }

exercises/05_vecs/vecs2.rs

@@ -9,26 +9,6 @@ fn vec_loop(input: &[i32]) -> Vec<i32> {
     output
 }
 
-fn vec_map_example(input: &[i32]) -> Vec<i32> {
-    // An example of collecting a vector after mapping.
-    // We map each element of the `input` slice to its value plus 1.
-    // If the input is `[1, 2, 3]`, the output is `[2, 3, 4]`.
-    input.iter().map(|element| element + 1).collect()
-}
-
-fn vec_map(input: &[i32]) -> Vec<i32> {
-    // TODO: Here, we also want to multiply each element in the `input` slice
-    // by 2, but with iterator mapping instead of manually pushing into an empty
-    // vector.
-    // See the example in the function `vec_map_example` above.
-    input
-        .iter()
-        .map(|element| {
-            // ???
-        })
-        .collect()
-}
-
 fn main() {
     // You can optionally experiment here.
 }
@@ -43,18 +23,4 @@ mod tests {
         let ans = vec_loop(&input);
         assert_eq!(ans, [4, 8, 12, 16, 20]);
     }
-
-    #[test]
-    fn test_vec_map_example() {
-        let input = [1, 2, 3];
-        let ans = vec_map_example(&input);
-        assert_eq!(ans, [2, 3, 4]);
-    }
-
-    #[test]
-    fn test_vec_map() {
-        let input = [2, 4, 6, 8, 10];
-        let ans = vec_map(&input);
-        assert_eq!(ans, [4, 8, 12, 16, 20]);
-    }
 }

exercises/08_enums/README.md

@@ -1,10 +1,10 @@
 # Enums
 
 Rust allows you to define types called "enums" which enumerate possible values.
-Enums are a feature in many languages, but their capabilities differ in each language. Rust’s enums are most similar to algebraic data types in functional languages, such as F#, OCaml, and Haskell.
+Enums are a feature in many languages, but their capabilities differ in each language. Rust's enums are most similar to algebraic data types in functional languages, such as F#, OCaml, and Haskell.
 Useful in combination with enums is Rust's "pattern matching" facility, which makes it easy to run different code for different values of an enumeration.
 
 ## Further information
 
 - [Enums](https://doc.rust-lang.org/book/ch06-00-enums.html)
-- [Pattern syntax](https://doc.rust-lang.org/book/ch18-03-pattern-syntax.html)
+- [Pattern syntax](https://doc.rust-lang.org/book/ch19-03-pattern-syntax.html)

exercises/08_enums/enums2.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 #[derive(Debug)]
 struct Point {
     x: u64,

exercises/08_enums/enums3.rs

@@ -4,7 +4,11 @@ struct Point {
 }
 
 enum Message {
-    // TODO: Implement the message variant types based on their usage below.
+    Resize { width: u64, height: u64 },
+    Move(Point),
+    Echo(String),
+    ChangeColor(u8, u8, u8),
+    Quit,
 }
 
 struct State {

exercises/09_strings/strings3.rs

@@ -23,6 +23,7 @@ mod tests {
         assert_eq!(trim_me("Hello!     "), "Hello!");
         assert_eq!(trim_me("  What's up!"), "What's up!");
         assert_eq!(trim_me("   Hola!  "), "Hola!");
+        assert_eq!(trim_me("Hi!"), "Hi!");
     }
 
     #[test]

exercises/10_modules/modules2.rs

@@ -1,7 +1,6 @@
 // You can bring module paths into scopes and provide new names for them with
 // the `use` and `as` keywords.
 
-#[allow(dead_code)]
 mod delicious_snacks {
     // TODO: Add the following two `use` statements after fixing them.
     // use self::fruits::PEAR as ???;

exercises/11_hashmaps/hashmaps2.rs

@@ -6,7 +6,7 @@
 // must add fruit to the basket so that there is at least one of each kind and
 // more than 11 in total - we have a lot of mouths to feed. You are not allowed
 // to insert any more of the fruits that are already in the basket (Apple,
-// Mango, and Lyche).
+// Mango, and Lychee).
 
 use std::collections::HashMap;
 

exercises/11_hashmaps/hashmaps3.rs

@@ -10,14 +10,14 @@ use std::collections::HashMap;
 
 // A structure to store the goal details of a team.
 #[derive(Default)]
-struct Team {
+struct TeamScores {
     goals_scored: u8,
     goals_conceded: u8,
 }
 
-fn build_scores_table(results: &str) -> HashMap<&str, Team> {
+fn build_scores_table(results: &str) -> HashMap<&str, TeamScores> {
     // The name of the team is the key and its associated struct is the value.
-    let mut scores = HashMap::new();
+    let mut scores = HashMap::<&str, TeamScores>::new();
 
     for line in results.lines() {
         let mut split_iterator = line.split(',');

exercises/12_options/options1.rs

@@ -1,8 +1,8 @@
-// This function returns how much icecream there is left in the fridge.
+// This function returns how much ice cream there is left in the fridge.
 // If it's before 22:00 (24-hour system), then 5 scoops are left. At 22:00,
-// someone eats it all, so no icecream is left (value 0). Return `None` if
+// someone eats it all, so no ice cream is left (value 0). Return `None` if
 // `hour_of_day` is higher than 23.
-fn maybe_icecream(hour_of_day: u16) -> Option<u16> {
+fn maybe_ice_cream(hour_of_day: u16) -> Option<u16> {
     // TODO: Complete the function body.
 }
 
@@ -18,19 +18,19 @@ mod tests {
     fn raw_value() {
         // TODO: Fix this test. How do you get the value contained in the
         // Option?
-        let icecreams = maybe_icecream(12);
+        let ice_creams = maybe_ice_cream(12);
 
-        assert_eq!(icecreams, 5); // Don't change this line.
+        assert_eq!(ice_creams, 5); // Don't change this line.
     }
 
     #[test]
-    fn check_icecream() {
+    fn check_ice_cream() {
-        assert_eq!(maybe_icecream(0), Some(5));
+        assert_eq!(maybe_ice_cream(0), Some(5));
-        assert_eq!(maybe_icecream(9), Some(5));
+        assert_eq!(maybe_ice_cream(9), Some(5));
-        assert_eq!(maybe_icecream(18), Some(5));
+        assert_eq!(maybe_ice_cream(18), Some(5));
-        assert_eq!(maybe_icecream(22), Some(0));
+        assert_eq!(maybe_ice_cream(22), Some(0));
-        assert_eq!(maybe_icecream(23), Some(0));
+        assert_eq!(maybe_ice_cream(23), Some(0));
-        assert_eq!(maybe_icecream(24), None);
+        assert_eq!(maybe_ice_cream(24), None);
-        assert_eq!(maybe_icecream(25), None);
+        assert_eq!(maybe_ice_cream(25), None);
     }
 }

exercises/12_options/options3.rs

@@ -9,7 +9,7 @@ fn main() {
 
     // TODO: Fix the compiler error by adding something to this match statement.
     match optional_point {
-        Some(p) => println!("Co-ordinates are {},{}", p.x, p.y),
+        Some(p) => println!("Coordinates are {},{}", p.x, p.y),
         _ => panic!("No match!"),
     }
 

exercises/13_error_handling/README.md

@@ -1,8 +1,8 @@
 # Error handling
 
-Most errors aren’t serious enough to require the program to stop entirely.
+Most errors aren't serious enough to require the program to stop entirely.
-Sometimes, when a function fails, it’s for a reason that you can easily interpret and respond to.
+Sometimes, when a function fails, it's for a reason that you can easily interpret and respond to.
-For example, if you try to open a file and that operation fails because the file doesn’t exist, you might want to create the file instead of terminating the process.
+For example, if you try to open a file and that operation fails because the file doesn't exist, you might want to create the file instead of terminating the process.
 
 ## Further information
 

exercises/13_error_handling/errors1.rs

@@ -6,7 +6,7 @@
 // of `Option<String>`.
 fn generate_nametag_text(name: String) -> Option<String> {
     if name.is_empty() {
-        // Empty names aren't allowed.
+        // Empty names aren't allowed
         None
     } else {
         Some(format!("Hi! My name is {name}"))

exercises/13_error_handling/errors4.rs

@@ -1,5 +1,3 @@
-#![allow(clippy::comparison_chain)]
-
 #[derive(PartialEq, Debug)]
 enum CreationError {
     Negative,
@@ -12,6 +10,7 @@ struct PositiveNonzeroInteger(u64);
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<Self, CreationError> {
         // TODO: This function shouldn't always return an `Ok`.
+        // Read the tests below to clarify what should be returned.
         Ok(Self(value as u64))
     }
 }

exercises/13_error_handling/errors5.rs

@@ -6,7 +6,7 @@
 //
 // In short, this particular use case for boxes is for when you want to own a
 // value and you care only that it is a type which implements a particular
-// trait. To do so, The `Box` is declared as of type `Box<dyn Trait>` where
+// trait. To do so, the `Box` is declared as of type `Box<dyn Trait>` where
 // `Trait` is the trait the compiler looks for on any value used in that
 // context. For this exercise, that context is the potential errors which
 // can be returned in a `Result`.

exercises/13_error_handling/errors6.rs

@@ -25,7 +25,7 @@ impl ParsePosNonzeroError {
     }
 
     // TODO: Add another error conversion function here.
-    // fn from_parseint(???) -> Self { ??? }
+    // fn from_parse_int(???) -> Self { ??? }
 }
 
 #[derive(PartialEq, Debug)]

exercises/15_traits/traits3.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 trait Licensed {
     // TODO: Add a default implementation for `licensing_info` so that
     // implementors like the two structs below can share that default behavior

exercises/17_tests/tests3.rs

@@ -9,7 +9,7 @@ impl Rectangle {
         if width <= 0 || height <= 0 {
             // Returning a `Result` would be better here. But we want to learn
             // how to test functions that can panic.
-            panic!("Rectangle width and height can't be negative");
+            panic!("Rectangle width and height must be positive");
         }
 
         Rectangle { width, height }

exercises/18_iterators/iterators3.rs

@@ -39,6 +39,8 @@ mod tests {
     #[test]
     fn test_success() {
         assert_eq!(divide(81, 9), Ok(9));
+        assert_eq!(divide(81, -1), Ok(-81));
+        assert_eq!(divide(i64::MIN, i64::MIN), Ok(1));
     }
 
     #[test]

exercises/19_smart_pointers/rc1.rs

@@ -8,7 +8,6 @@ use std::rc::Rc;
 #[derive(Debug)]
 struct Sun;
 
-#[allow(dead_code)]
 #[derive(Debug)]
 enum Planet {
     Mercury(Rc<Sun>),

exercises/20_threads/threads1.rs

@@ -1,5 +1,5 @@
-// This program spawns multiple threads that each run for at least 250ms, and
+// This program spawns multiple threads that each runs for at least 250ms, and
-// each thread returns how much time they took to complete. The program should
+// each thread returns how much time it took to complete. The program should
 // wait until all the spawned threads have finished and should collect their
 // return values into a vector.
 

exercises/20_threads/threads3.rs

@@ -1,7 +1,6 @@
 use std::{sync::mpsc, thread, time::Duration};
 
 struct Queue {
-    length: u32,
     first_half: Vec<u32>,
     second_half: Vec<u32>,
 }
@@ -9,7 +8,6 @@ struct Queue {
 impl Queue {
     fn new() -> Self {
         Self {
-            length: 10,
             first_half: vec![1, 2, 3, 4, 5],
             second_half: vec![6, 7, 8, 9, 10],
         }
@@ -48,17 +46,15 @@ mod tests {
     fn threads3() {
         let (tx, rx) = mpsc::channel();
         let queue = Queue::new();
-        let queue_length = queue.length;
 
         send_tx(queue, tx);
 
-        let mut total_received: u32 = 0;
+        let mut received = Vec::with_capacity(10);
-        for received in rx {
+        for value in rx {
-            println!("Got: {received}");
+            received.push(value);
-            total_received += 1;
         }
 
-        println!("Number of received values: {total_received}");
+        received.sort();
-        assert_eq!(total_received, queue_length);
+        assert_eq!(received, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
     }
 }

exercises/21_macros/README.md

@@ -10,5 +10,6 @@ of exercises to Rustlings, but is all about learning to write Macros.
 
 ## Further information
 
-- [Macros](https://doc.rust-lang.org/book/ch19-06-macros.html)
+- [The Rust Book - Macros](https://doc.rust-lang.org/book/ch20-05-macros.html)
 - [The Little Book of Rust Macros](https://veykril.github.io/tlborm/)
+- [Rust by Example - macro_rules!](https://doc.rust-lang.org/rust-by-example/macros.html)

exercises/22_clippy/clippy3.rs

@@ -1,22 +1,25 @@
-// Here are some more easy Clippy fixes so you can see its utility 📎
+// Here are some more easy Clippy fixes so you can see its utility.
 // TODO: Fix all the Clippy lints.
 
-#[rustfmt::skip]
 #[allow(unused_variables, unused_assignments)]
 fn main() {
-    let my_option: Option<()> = None;
+    let my_option: Option<&str> = None;
+    // Assume that you don't know the value of `my_option`.
+    // In the case of `Some`, we want to print its value.
     if my_option.is_none() {
-        println!("{:?}", my_option.unwrap());
+        println!("{}", my_option.unwrap());
     }
 
+    #[rustfmt::skip]
     let my_arr = &[
         -1, -2, -3
         -4, -5, -6
     ];
     println!("My array! Here it is: {my_arr:?}");
 
-    let my_empty_vec = vec![1, 2, 3, 4, 5].resize(0, 5);
+    let mut my_vec = vec![1, 2, 3, 4, 5];
-    println!("This Vec is empty, see? {my_empty_vec:?}");
+    my_vec.resize(0, 5);
+    println!("This Vec is empty, see? {my_vec:?}");
 
     let mut value_a = 45;
     let mut value_b = 66;

exercises/23_conversions/as_ref_mut.rs

@@ -2,10 +2,11 @@
 // about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html and
 // https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
 
-// Obtain the number of bytes (not characters) in the given argument.
+// Obtain the number of bytes (not characters) in the given argument
+// (`.len()` returns the number of bytes in a string).
 // TODO: Add the `AsRef` trait appropriately as a trait bound.
 fn byte_counter<T>(arg: T) -> usize {
-    arg.as_ref().as_bytes().len()
+    arg.as_ref().len()
 }
 
 // Obtain the number of characters (not bytes) in the given argument.

exercises/23_conversions/from_str.rs

@@ -25,7 +25,7 @@ enum ParsePersonError {
     ParseInt(ParseIntError),
 }
 
-// TODO: Complete this `From` implementation to be able to parse a `Person`
+// TODO: Complete this `FromStr` implementation to be able to parse a `Person`
 // out of a string in the form of "Mark,20".
 // Note that you'll need to parse the age component into a `u8` with something
 // like `"4".parse::<u8>()`.

exercises/README.md

@@ -9,7 +9,7 @@
 | vecs                   | §8.1                |
 | move_semantics         | §4.1-2              |
 | structs                | §5.1, §5.3          |
-| enums                  | §6, §18.3           |
+| enums                  | §6, §19.3           |
 | strings                | §8.2                |
 | modules                | §7                  |
 | hashmaps               | §8.3                |
@@ -22,6 +22,6 @@
 | iterators              | §13.2-4             |
 | smart_pointers         | §15, §16.3          |
 | threads                | §16.1-3             |
-| macros                 | §19.5               |
+| macros                 | §20.5               |
-| clippy                 | §21.4               |
+| clippy                 | Appendix D          |
 | conversions            | n/a                 |

exercises/quizzes/quiz2.rs

@@ -26,7 +26,7 @@ enum Command {
 mod my_module {
     use super::Command;
 
-    // TODO: Complete the function.
+    // TODO: Complete the function as described above.
     // pub fn transformer(input: ???) -> ??? { ??? }
 }
 

oranda.json

@@ -1,13 +0,0 @@
-{
-  "project": {
-    "homepage": "https://rustlings.cool",
-    "repository": "https://github.com/rust-lang/rustlings"
-  },
-  "marketing": {
-    "analytics": {
-      "plausible": {
-        "domain": "rustlings.cool"
-      }
-    }
-  }
-}

release-hook.sh

@@ -3,7 +3,14 @@
 # Error out if any command fails
 set -e
 
-cargo run -- dev check
 typos
-cargo outdated -w --exit-code 1
+cargo upgrades
-cargo test --workspace --all-targets
+
+# Similar to CI
+cargo clippy -- --deny warnings
+cargo fmt --all --check
+cargo test --workspace
+cargo dev check --require-solutions
+
+# MSRV
+cargo +1.88 dev check --require-solutions

rustlings-macros/Cargo.toml

@@ -6,6 +6,7 @@ authors.workspace = true
 repository.workspace = true
 license.workspace = true
 edition.workspace = true
+rust-version.workspace = true
 include = [
   "/src/",
   "/info.toml",
@@ -15,6 +16,9 @@ include = [
 proc-macro = true
 
 [dependencies]
-quote = "1.0.36"
+quote = "1.0"
 serde.workspace = true
-toml_edit.workspace = true
+toml.workspace = true
+
+[lints]
+workspace = true

rustlings-macros/info.toml

@@ -1,6 +1,7 @@
 format_version = 1
 
-welcome_message = """Is this your first time? Don't worry, Rustlings is made for beginners!
+welcome_message = """
+Is this your first time? Don't worry, Rustlings is made for beginners!
 We are going to teach you a lot of things about Rust, but before we can
 get started, here are some notes about how Rustlings operates:
 
@@ -10,15 +11,16 @@ get started, here are some notes about how Rustlings operates:
    and fix them!
 2. Make sure to have your editor open in the `rustlings/` directory. Rustlings
    will show you the path of the current exercise under the progress bar. Open
-   the exercise file in your editor, fix errors and save the file. Rustlings will
+   the exercise file in your editor, fix errors and save the file. Rustlings
-   automatically detect the file change and rerun the exercise. If all errors are
+   will automatically detect the file change and rerun the exercise. If all
-   fixed, Rustlings will ask you to move on to the next exercise.
+   errors are fixed, Rustlings will ask you to move on to the next exercise.
 3. If you're stuck on an exercise, enter `h` to show a hint.
-4. If an exercise doesn't make sense to you, feel free to open an issue on GitHub!
+4. If an exercise doesn't make sense to you, feel free to open an issue on
-   (https://github.com/rust-lang/rustlings). We look at every issue, and sometimes,
+   GitHub! (https://github.com/rust-lang/rustlings). We look at every issue, and
-   other learners do too so you can help each other out!"""
+   sometimes, other learners do too so you can help each other out!"""
 
-final_message = """We hope you enjoyed learning about the various aspects of Rust!
+final_message = """
+We hope you enjoyed learning about the various aspects of Rust!
 If you noticed any issues, don't hesitate to report them on Github.
 You can also contribute your own exercises to help the greater community!
 
@@ -120,10 +122,10 @@ dir = "01_variables"
 test = false
 hint = """
 We know about variables and mutability, but there is another important type of
-variables available: constants.
+variable available: constants.
 
-Constants are always immutable. They are declared with the keyword `const` instead
+Constants are always immutable. They are declared with the keyword `const`
-of `let`.
+instead of `let`.
 
 The type of Constants must always be annotated.
 
@@ -253,7 +255,7 @@ require you to type in 100 items (but you certainly can if you want!).
 
 For example, you can do:
 ```
-let array = ["Are we there yet?"; 10];
+let array = ["Are we there yet?"; 100];
 ```
 
 Bonus: what are some other things you could have that would return `true`
@@ -316,15 +318,7 @@ of the Rust book to learn more."""
 name = "vecs2"
 dir = "05_vecs"
 hint = """
-In the first function, we create an empty vector and want to push new elements
+Use the `.push()` method on the vector to push new elements to it."""
-to it.
-
-In the second function, we map the values of the input and collect them into a vector.
-
-After you've completed both functions, decide for yourself which approach you
-like better.
-
-What do you think is the more commonly used pattern under Rust developers?"""
 
 # MOVE SEMANTICS
 
@@ -332,8 +326,8 @@ What do you think is the more commonly used pattern under Rust developers?"""
 name = "move_semantics1"
 dir = "06_move_semantics"
 hint = """
-So you've got the "cannot borrow `vec` as mutable, as it is not declared as mutable"
+So you've got the "cannot borrow `vec` as mutable, as it is not declared as
-error on the line where we push an element to the vector, right?
+mutable" error on the line where we push an element to the vector, right?
 
 The fix for this is going to be adding one keyword, and the addition is NOT on
 the line where we push to the vector (where the error is).
@@ -369,7 +363,8 @@ hint = """
 Carefully reason about the range in which each mutable reference is in
 scope. Does it help to update the value of `x` immediately after
 the mutable reference is taken?
-Read more about 'Mutable References' in the book's section 'References and Borrowing':
+Read more about 'Mutable References' in the book's section 'References and
+Borrowing':
 https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#mutable-references."""
 
 [[exercises]]
@@ -498,14 +493,18 @@ some of them:
 https://doc.rust-lang.org/std/string/struct.String.html#method.trim
 
 For the `compose_me` method: You can either use the `format!` macro, or convert
-the string slice into an owned string, which you can then freely extend."""
+the string slice into an owned string, which you can then freely extend.
+
+For the `replace_me` method, you can check out the `replace` method:
+https://doc.rust-lang.org/std/string/struct.String.html#method.replace"""
 
 [[exercises]]
 name = "strings4"
 dir = "09_strings"
 test = false
 hint = """
-Replace `placeholder` with either `string` or `string_slice` in the `main` function.
+Replace `placeholder` with either `string` or `string_slice` in the `main`
+function.
 
 Example:
 `placeholder("blue");`
@@ -567,12 +566,8 @@ https://doc.rust-lang.org/book/ch08-03-hash-maps.html#only-inserting-a-value-if-
 name = "hashmaps3"
 dir = "11_hashmaps"
 hint = """
-Hint 1: Use the `entry()` and `or_insert()` (or `or_insert_with()`) methods of
+Hint 1: Use the `entry()` and `or_default()` methods of `HashMap` to insert the
-        `HashMap` to insert the default value of `Team` if a team doesn't
+        default value of `TeamScores` if a team doesn't exist in the table yet.
-        exist in the table yet.
-
-Learn more in The Book:
-https://doc.rust-lang.org/book/ch08-03-hash-maps.html#only-inserting-a-value-if-the-key-has-no-value
 
 Hint 2: If there is already an entry for a given key, the value returned by
         `entry()` can be updated based on the existing value.
@@ -760,7 +755,7 @@ Notice how the trait takes ownership of `self` and returns `Self`.
 
 Although the signature of `append_bar` in the trait takes `self` as argument,
 the implementation can take `mut self` instead. This is possible because the
-the value is owned anyway."""
+value is owned anyway."""
 
 [[exercises]]
 name = "traits3"
@@ -1136,7 +1131,7 @@ constants, but clippy recognizes those imprecise mathematical constants as a
 source of potential error.
 
 See the suggestions of the Clippy warning in the compile output and use the
-appropriate replacement constant from `std::f32::consts`..."""
+appropriate replacement constant from `std::f32::consts`."""
 
 [[exercises]]
 name = "clippy2"
@@ -1197,7 +1192,8 @@ hint = """
 Is there an implementation of `TryFrom` in the standard library that can both do
 the required integer conversion and check the range of the input?
 
-Challenge: Can you make the `TryFrom` implementations generic over many integer types?"""
+Challenge: Can you make the `TryFrom` implementations generic over many integer
+types?"""
 
 [[exercises]]
 name = "as_ref_mut"

rustlings-macros/src/lib.rs

@@ -16,7 +16,7 @@ struct InfoFile {
 #[proc_macro]
 pub fn include_files(_: TokenStream) -> TokenStream {
     let info_file = include_str!("../info.toml");
-    let exercises = toml_edit::de::from_str::<InfoFile>(info_file)
+    let exercises = toml::de::from_str::<InfoFile>(info_file)
         .expect("Failed to parse `info.toml`")
         .exercises;
 

solutions/01_variables/variables5.rs

@@ -1,6 +1,6 @@
 fn main() {
     let number = "T-H-R-E-E";
-    println!("Spell a number: {}", number);
+    println!("Spell a number: {number}");
 
     // Using variable shadowing
     // https://doc.rust-lang.org/book/ch03-01-variables-and-mutability.html#shadowing

solutions/02_functions/functions3.rs

@@ -1,4 +1,4 @@
-fn call_me(num: u32) {
+fn call_me(num: u8) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

solutions/03_if/if1.rs

@@ -1,9 +1,5 @@
 fn bigger(a: i32, b: i32) -> i32 {
-    if a > b {
+    if a > b { a } else { b }
-        a
-    } else {
-        b
-    }
 }
 
 fn main() {

solutions/03_if/if2.rs

@@ -1,10 +1,10 @@
-fn foo_if_fizz(fizzish: &str) -> &str {
+fn picky_eater(food: &str) -> &str {
-    if fizzish == "fizz" {
+    if food == "strawberry" {
-        "foo"
+        "Yummy!"
-    } else if fizzish == "fuzz" {
+    } else if food == "potato" {
-        "bar"
+        "I guess I can eat that."
     } else {
-        "baz"
+        "No thanks!"
     }
 }
 
@@ -17,17 +17,19 @@ mod tests {
     use super::*;
 
     #[test]
-    fn foo_for_fizz() {
+    fn yummy_food() {
-        assert_eq!(foo_if_fizz("fizz"), "foo");
+        assert_eq!(picky_eater("strawberry"), "Yummy!");
     }
 
     #[test]
-    fn bar_for_fuzz() {
+    fn neutral_food() {
-        assert_eq!(foo_if_fizz("fuzz"), "bar");
+        assert_eq!(picky_eater("potato"), "I guess I can eat that.");
     }
 
     #[test]
-    fn default_to_baz() {
+    fn default_disliked_food() {
-        assert_eq!(foo_if_fizz("literally anything"), "baz");
+        assert_eq!(picky_eater("broccoli"), "No thanks!");
+        assert_eq!(picky_eater("gummy bears"), "No thanks!");
+        assert_eq!(picky_eater("literally anything"), "No thanks!");
     }
 }

solutions/05_vecs/vecs2.rs

@@ -8,22 +8,6 @@ fn vec_loop(input: &[i32]) -> Vec<i32> {
     output
 }
 
-fn vec_map_example(input: &[i32]) -> Vec<i32> {
-    // An example of collecting a vector after mapping.
-    // We map each element of the `input` slice to its value plus 1.
-    // If the input is `[1, 2, 3]`, the output is `[2, 3, 4]`.
-    input.iter().map(|element| element + 1).collect()
-}
-
-fn vec_map(input: &[i32]) -> Vec<i32> {
-    // We will dive deeper into iterators, but for now, this is all what you
-    // had to do!
-    // Advanced note: This method is more efficient because it automatically
-    // preallocates enough capacity. This can be done manually in `vec_loop`
-    // using `Vec::with_capacity(input.len())` instead of `Vec::new()`.
-    input.iter().map(|element| 2 * element).collect()
-}
-
 fn main() {
     // You can optionally experiment here.
 }
@@ -38,18 +22,4 @@ mod tests {
         let ans = vec_loop(&input);
         assert_eq!(ans, [4, 8, 12, 16, 20]);
     }
-
-    #[test]
-    fn test_vec_map_example() {
-        let input = [1, 2, 3];
-        let ans = vec_map_example(&input);
-        assert_eq!(ans, [2, 3, 4]);
-    }
-
-    #[test]
-    fn test_vec_map() {
-        let input = [2, 4, 6, 8, 10];
-        let ans = vec_map(&input);
-        assert_eq!(ans, [4, 8, 12, 16, 20]);
-    }
 }

solutions/06_move_semantics/move_semantics4.rs

@@ -4,8 +4,6 @@ fn main() {
 
 #[cfg(test)]
 mod tests {
-    // TODO: Fix the compiler errors only by reordering the lines in the test.
-    // Don't add, change or remove any line.
     #[test]
     fn move_semantics4() {
         let mut x = Vec::new();

solutions/08_enums/enums2.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 #[derive(Debug)]
 struct Point {
     x: u64,

solutions/08_enums/enums3.rs

@@ -46,8 +46,8 @@ impl State {
         match message {
             Message::Resize { width, height } => self.resize(width, height),
             Message::Move(point) => self.move_position(point),
-            Message::Echo(s) => self.echo(s),
+            Message::Echo(string) => self.echo(string),
-            Message::ChangeColor(r, g, b) => self.change_color(r, g, b),
+            Message::ChangeColor(red, green, blue) => self.change_color(red, green, blue),
             Message::Quit => self.quit(),
         }
     }

solutions/09_strings/strings3.rs

@@ -26,6 +26,7 @@ mod tests {
         assert_eq!(trim_me("Hello!     "), "Hello!");
         assert_eq!(trim_me("  What's up!"), "What's up!");
         assert_eq!(trim_me("   Hola!  "), "Hola!");
+        assert_eq!(trim_me("Hi!"), "Hi!");
     }
 
     #[test]

solutions/09_strings/strings4.rs

@@ -18,12 +18,11 @@ fn main() {
     // Here, both answers work.
     // `.into()` converts a type into an expected type.
     // If it is called where `String` is expected, it will convert `&str` to `String`.
-    // But if is called where `&str` is expected, then `&str` is kept `&str` since no
-    // conversion is needed.
     string("nice weather".into());
+    // But if it is called where `&str` is expected, then `&str` is kept as `&str` since no conversion is needed.
+    // If you remove the `#[allow(…)]` line, then Clippy will tell you to remove `.into()` below since it is a useless conversion.
+    #[allow(clippy::useless_conversion)]
     string_slice("nice weather".into());
-    //                         ^^^^^^^ the compiler recommends removing the `.into()`
-    //                                 call because it is a useless conversion.
 
     string(format!("Interpolation {}", "Station"));
 

solutions/10_modules/modules2.rs

@@ -1,4 +1,3 @@
-#[allow(dead_code)]
 mod delicious_snacks {
     // Added `pub` and used the expected alias after `as`.
     pub use self::fruits::PEAR as fruit;

solutions/11_hashmaps/hashmaps1.rs

@@ -1,7 +1,7 @@
 // A basket of fruits in the form of a hash map needs to be defined. The key
 // represents the name of the fruit and the value represents how many of that
 // particular fruit is in the basket. You have to put at least 3 different
-// types of fruits (e.g apple, banana, mango) in the basket and the total count
+// types of fruits (e.g. apple, banana, mango) in the basket and the total count
 // of all the fruits should be at least 5.
 
 use std::collections::HashMap;

solutions/11_hashmaps/hashmaps2.rs

@@ -5,7 +5,8 @@
 // Apple (4), Mango (2) and Lychee (5) are already in the basket hash map. You
 // must add fruit to the basket so that there is at least one of each kind and
 // more than 11 in total - we have a lot of mouths to feed. You are not allowed
-// to insert any more of these fruits!
+// to insert any more of the fruits that are already in the basket (Apple,
+// Mango, and Lychee).
 
 use std::collections::HashMap;
 

solutions/11_hashmaps/hashmaps3.rs

@@ -10,14 +10,14 @@ use std::collections::HashMap;
 
 // A structure to store the goal details of a team.
 #[derive(Default)]
-struct Team {
+struct TeamScores {
     goals_scored: u8,
     goals_conceded: u8,
 }
 
-fn build_scores_table(results: &str) -> HashMap<&str, Team> {
+fn build_scores_table(results: &str) -> HashMap<&str, TeamScores> {
     // The name of the team is the key and its associated struct is the value.
-    let mut scores = HashMap::new();
+    let mut scores = HashMap::<&str, TeamScores>::new();
 
     for line in results.lines() {
         let mut split_iterator = line.split(',');
@@ -28,13 +28,13 @@ fn build_scores_table(results: &str) -> HashMap<&str, Team> {
         let team_2_score: u8 = split_iterator.next().unwrap().parse().unwrap();
 
         // Insert the default with zeros if a team doesn't exist yet.
-        let team_1 = scores.entry(team_1_name).or_insert_with(Team::default);
+        let team_1 = scores.entry(team_1_name).or_default();
         // Update the values.
         team_1.goals_scored += team_1_score;
         team_1.goals_conceded += team_2_score;
 
-        // Similarely for the second team.
+        // Similarly for the second team.
-        let team_2 = scores.entry(team_2_name).or_insert_with(Team::default);
+        let team_2 = scores.entry(team_2_name).or_default();
         team_2.goals_scored += team_2_score;
         team_2.goals_conceded += team_1_score;
     }
@@ -60,9 +60,11 @@ England,Spain,1,0";
     fn build_scores() {
         let scores = build_scores_table(RESULTS);
 
-        assert!(["England", "France", "Germany", "Italy", "Poland", "Spain"]
+        assert!(
-            .into_iter()
+            ["England", "France", "Germany", "Italy", "Poland", "Spain"]
-            .all(|team_name| scores.contains_key(team_name)));
+                .into_iter()
+                .all(|team_name| scores.contains_key(team_name))
+        );
     }
 
     #[test]

solutions/12_options/options1.rs

@@ -1,8 +1,8 @@
-// This function returns how much icecream there is left in the fridge.
+// This function returns how much ice cream there is left in the fridge.
 // If it's before 22:00 (24-hour system), then 5 scoops are left. At 22:00,
-// someone eats it all, so no icecream is left (value 0). Return `None` if
+// someone eats it all, so no ice cream is left (value 0). Return `None` if
 // `hour_of_day` is higher than 23.
-fn maybe_icecream(hour_of_day: u16) -> Option<u16> {
+fn maybe_ice_cream(hour_of_day: u16) -> Option<u16> {
     match hour_of_day {
         0..=21 => Some(5),
         22..=23 => Some(0),
@@ -21,19 +21,19 @@ mod tests {
     #[test]
     fn raw_value() {
         // Using `unwrap` is fine in a test.
-        let icecreams = maybe_icecream(12).unwrap();
+        let ice_creams = maybe_ice_cream(12).unwrap();
 
-        assert_eq!(icecreams, 5);
+        assert_eq!(ice_creams, 5);
     }
 
     #[test]
-    fn check_icecream() {
+    fn check_ice_cream() {
-        assert_eq!(maybe_icecream(0), Some(5));
+        assert_eq!(maybe_ice_cream(0), Some(5));
-        assert_eq!(maybe_icecream(9), Some(5));
+        assert_eq!(maybe_ice_cream(9), Some(5));
-        assert_eq!(maybe_icecream(18), Some(5));
+        assert_eq!(maybe_ice_cream(18), Some(5));
-        assert_eq!(maybe_icecream(22), Some(0));
+        assert_eq!(maybe_ice_cream(22), Some(0));
-        assert_eq!(maybe_icecream(23), Some(0));
+        assert_eq!(maybe_ice_cream(23), Some(0));
-        assert_eq!(maybe_icecream(24), None);
+        assert_eq!(maybe_ice_cream(24), None);
-        assert_eq!(maybe_icecream(25), None);
+        assert_eq!(maybe_ice_cream(25), None);
     }
 }

solutions/12_options/options3.rs

@@ -10,7 +10,7 @@ fn main() {
     // Solution 1: Matching over the `Option` (not `&Option`) but without moving
     // out of the `Some` variant.
     match optional_point {
-        Some(ref p) => println!("Co-ordinates are {},{}", p.x, p.y),
+        Some(ref p) => println!("Coordinates are {},{}", p.x, p.y),
         //   ^^^ added
         _ => panic!("No match!"),
     }
@@ -18,7 +18,8 @@ fn main() {
     // Solution 2: Matching over a reference (`&Option`) by added `&` before
     // `optional_point`.
     match &optional_point {
-        Some(p) => println!("Co-ordinates are {},{}", p.x, p.y),
+        //^ added
+        Some(p) => println!("Coordinates are {},{}", p.x, p.y),
         _ => panic!("No match!"),
     }
 

solutions/13_error_handling/errors2.rs

@@ -16,7 +16,7 @@
 
 use std::num::ParseIntError;
 
-#[allow(unused_variables)]
+#[allow(unused_variables, clippy::question_mark)]
 fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;

solutions/13_error_handling/errors4.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::comparison_chain)]
+use std::cmp::Ordering;
 
 #[derive(PartialEq, Debug)]
 enum CreationError {
@@ -11,12 +11,10 @@ struct PositiveNonzeroInteger(u64);
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<Self, CreationError> {
-        if value == 0 {
+        match value.cmp(&0) {
-            Err(CreationError::Zero)
+            Ordering::Less => Err(CreationError::Negative),
-        } else if value < 0 {
+            Ordering::Equal => Err(CreationError::Zero),
-            Err(CreationError::Negative)
+            Ordering::Greater => Ok(Self(value as u64)),
-        } else {
-            Ok(Self(value as u64))
         }
     }
 }

solutions/13_error_handling/errors5.rs

@@ -6,7 +6,7 @@
 //
 // In short, this particular use case for boxes is for when you want to own a
 // value and you care only that it is a type which implements a particular
-// trait. To do so, The `Box` is declared as of type `Box<dyn Trait>` where
+// trait. To do so, the `Box` is declared as of type `Box<dyn Trait>` where
 // `Trait` is the trait the compiler looks for on any value used in that
 // context. For this exercise, that context is the potential errors which
 // can be returned in a `Result`.

solutions/13_error_handling/errors6.rs

@@ -24,11 +24,26 @@ impl ParsePosNonzeroError {
         Self::Creation(err)
     }
 
-    fn from_parseint(err: ParseIntError) -> Self {
+    fn from_parse_int(err: ParseIntError) -> Self {
         Self::ParseInt(err)
     }
 }
 
+// As an alternative solution, implementing the `From` trait allows for the
+// automatic conversion from a `ParseIntError` into a `ParsePosNonzeroError`
+// using the `?` operator, without the need to call `map_err`.
+//
+// ```
+// let x: i64 = s.parse()?;
+// ```
+//
+// Traits like `From` will be dealt with in later exercises.
+impl From<ParseIntError> for ParsePosNonzeroError {
+    fn from(err: ParseIntError) -> Self {
+        ParsePosNonzeroError::ParseInt(err)
+    }
+}
+
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
@@ -44,7 +59,7 @@ impl PositiveNonzeroInteger {
     fn parse(s: &str) -> Result<Self, ParsePosNonzeroError> {
         // Return an appropriate error instead of panicking when `parse()`
         // returns an error.
-        let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
+        let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parse_int)?;
         //                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         Self::new(x).map_err(ParsePosNonzeroError::from_creation)
     }

solutions/15_traits/traits3.rs

@@ -1,5 +1,3 @@
-#![allow(dead_code)]
-
 trait Licensed {
     fn licensing_info(&self) -> String {
         "Default license".to_string()

solutions/16_lifetimes/lifetimes1.rs

@@ -5,11 +5,7 @@
 
 fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
     //    ^^^^     ^^          ^^          ^^
-    if x.len() > y.len() {
+    if x.len() > y.len() { x } else { y }
-        x
-    } else {
-        y
-    }
 }
 
 fn main() {

solutions/16_lifetimes/lifetimes2.rs

@@ -1,14 +1,10 @@
 fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
-    if x.len() > y.len() {
+    if x.len() > y.len() { x } else { y }
-        x
-    } else {
-        y
-    }
 }
 
 fn main() {
     let string1 = String::from("long string is long");
-    // Solution1: You can move `strings2` out of the inner block so that it is
+    // Solution 1: You can move `strings2` out of the inner block so that it is
     // not dropped before the print statement.
     let string2 = String::from("xyz");
     let result;
@@ -25,7 +21,7 @@ fn main() {
     {
         let string2 = String::from("xyz");
         result = longest(&string1, &string2);
-        // Solution2: You can move the print statement into the inner block so
+        // Solution 2: You can move the print statement into the inner block so
         // that it is executed before `string2` is dropped.
         println!("The longest string is '{result}'");
         // `string2` dropped here (end of the inner scope).

solutions/17_tests/tests3.rs

@@ -9,7 +9,7 @@ impl Rectangle {
         if width <= 0 || height <= 0 {
             // Returning a `Result` would be better here. But we want to learn
             // how to test functions that can panic.
-            panic!("Rectangle width and height can't be negative");
+            panic!("Rectangle width and height must be positive");
         }
 
         Rectangle { width, height }

solutions/18_iterators/iterators3.rs

@@ -52,6 +52,8 @@ mod tests {
     #[test]
     fn test_success() {
         assert_eq!(divide(81, 9), Ok(9));
+        assert_eq!(divide(81, -1), Ok(-81));
+        assert_eq!(divide(i64::MIN, i64::MIN), Ok(1));
     }
 
     #[test]

solutions/18_iterators/iterators4.rs

@@ -25,6 +25,7 @@ fn factorial_fold(num: u64) -> u64 {
     //              -> 1 * 2 is calculated, then the result 2 is multiplied by
     //                 the second element 3 so the result 6 is returned.
     // And so on…
+    #[allow(clippy::unnecessary_fold)]
     (2..=num).fold(1, |acc, x| acc * x)
 }
 

solutions/19_smart_pointers/rc1.rs

@@ -8,7 +8,6 @@ use std::rc::Rc;
 #[derive(Debug)]
 struct Sun;
 
-#[allow(dead_code)]
 #[derive(Debug)]
 enum Planet {
     Mercury(Rc<Sun>),
@@ -64,12 +63,10 @@ mod tests {
         println!("reference count = {}", Rc::strong_count(&sun)); // 7 references
         saturn.details();
 
-        // TODO
         let uranus = Planet::Uranus(Rc::clone(&sun));
         println!("reference count = {}", Rc::strong_count(&sun)); // 8 references
         uranus.details();
 
-        // TODO
         let neptune = Planet::Neptune(Rc::clone(&sun));
         println!("reference count = {}", Rc::strong_count(&sun)); // 9 references
         neptune.details();

solutions/20_threads/threads1.rs

@@ -1,5 +1,5 @@
-// This program spawns multiple threads that each run for at least 250ms, and
+// This program spawns multiple threads that each runs for at least 250ms, and
-// each thread returns how much time they took to complete. The program should
+// each thread returns how much time it took to complete. The program should
 // wait until all the spawned threads have finished and should collect their
 // return values into a vector.
 

solutions/20_threads/threads3.rs

@@ -1,7 +1,6 @@
 use std::{sync::mpsc, thread, time::Duration};
 
 struct Queue {
-    length: u32,
     first_half: Vec<u32>,
     second_half: Vec<u32>,
 }
@@ -9,7 +8,6 @@ struct Queue {
 impl Queue {
     fn new() -> Self {
         Self {
-            length: 10,
             first_half: vec![1, 2, 3, 4, 5],
             second_half: vec![6, 7, 8, 9, 10],
         }
@@ -50,17 +48,15 @@ mod tests {
     fn threads3() {
         let (tx, rx) = mpsc::channel();
         let queue = Queue::new();
-        let queue_length = queue.length;
 
         send_tx(queue, tx);
 
-        let mut total_received: u32 = 0;
+        let mut received = Vec::with_capacity(10);
-        for received in rx {
+        for value in rx {
-            println!("Got: {received}");
+            received.push(value);
-            total_received += 1;
         }
 
-        println!("Number of received values: {total_received}");
+        received.sort();
-        assert_eq!(total_received, queue_length);
+        assert_eq!(received, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
     }
 }

solutions/21_macros/macros3.rs

@@ -1,4 +1,4 @@
-// Added the attribute `macro_use` attribute.
+// Added the `macro_use` attribute.
 #[macro_use]
 mod macros {
     macro_rules! my_macro {

solutions/22_clippy/clippy3.rs

@@ -1,31 +1,31 @@
 use std::mem;
 
-#[rustfmt::skip]
 #[allow(unused_variables, unused_assignments)]
 fn main() {
-    let my_option: Option<()> = None;
+    let my_option: Option<&str> = None;
     // `unwrap` of an `Option` after checking if it is `None` will panic.
     // Use `if-let` instead.
     if let Some(value) = my_option {
-        println!("{value:?}");
+        println!("{value}");
     }
 
     // A comma was missing.
+    #[rustfmt::skip]
     let my_arr = &[
         -1, -2, -3,
         -4, -5, -6,
     ];
-    println!("My array! Here it is: {:?}", my_arr);
+    println!("My array! Here it is: {my_arr:?}");
 
-    let mut my_empty_vec = vec![1, 2, 3, 4, 5];
+    let mut my_vec = vec![1, 2, 3, 4, 5];
     // `resize` mutates a vector instead of returning a new one.
     // `resize(0, …)` clears a vector, so it is better to use `clear`.
-    my_empty_vec.clear();
+    my_vec.clear();
-    println!("This Vec is empty, see? {my_empty_vec:?}");
+    println!("This Vec is empty, see? {my_vec:?}");
 
     let mut value_a = 45;
     let mut value_b = 66;
     // Use `mem::swap` to correctly swap two values.
     mem::swap(&mut value_a, &mut value_b);
-    println!("value a: {}; value b: {}", value_a, value_b);
+    println!("value a: {value_a}; value b: {value_b}");
 }

solutions/23_conversions/as_ref_mut.rs

@@ -2,9 +2,10 @@
 // about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html and
 // https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
 
-// Obtain the number of bytes (not characters) in the given argument.
+// Obtain the number of bytes (not characters) in the given argument
+// (`.len()` returns the number of bytes in a string).
 fn byte_counter<T: AsRef<str>>(arg: T) -> usize {
-    arg.as_ref().as_bytes().len()
+    arg.as_ref().len()
 }
 
 // Obtain the number of characters (not bytes) in the given argument.

solutions/README.md

@@ -0,0 +1,6 @@
+# Official Rustlings solutions
+
+Before you finish an exercise, its solution file will only contain an empty `main` function.
+The content of this file will be automatically replaced by the actual solution once you finish the exercise.
+
+Note that these solutions are often only _one possibility_ to solve an exercise.

solutions/quizzes/quiz2.rs

@@ -62,8 +62,8 @@ mod tests {
     // Import `transformer`.
     use super::my_module::transformer;
 
-    use super::my_module::transformer_iter;
     use super::Command;
+    use super::my_module::transformer_iter;
 
     #[test]
     fn it_works() {

src/app_state.rs

@@ -1,32 +1,39 @@
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Error, Result, bail};
-use crossterm::style::Stylize;
+use crossterm::{QueueableCommand, cursor, terminal};
-use serde::Deserialize;
 use std::{
-    fs::{self, File},
+    collections::HashSet,
-    io::{Read, StdoutLock, Write},
+    env,
-    path::{Path, PathBuf},
+    fs::{File, OpenOptions},
+    io::{Read, Seek, StdoutLock, Write},
+    path::{MAIN_SEPARATOR_STR, Path},
     process::{Command, Stdio},
+    sync::{
+        atomic::{AtomicUsize, Ordering::Relaxed},
+        mpsc,
+    },
+    thread,
 };
 
 use crate::{
     clear_terminal,
+    cmd::CmdRunner,
     embedded::EMBEDDED_FILES,
-    exercise::{Exercise, RunnableExercise, OUTPUT_CAPACITY},
+    exercise::{Exercise, RunnableExercise},
     info_file::ExerciseInfo,
-    DEBUG_PROFILE,
+    term::{self, CheckProgressVisualizer},
 };
 
 const STATE_FILE_NAME: &str = ".rustlings-state.txt";
-const BAD_INDEX_ERR: &str = "The current exercise index is higher than the number of exercises";
+const DEFAULT_CHECK_PARALLELISM: usize = 8;
 
 #[must_use]
 pub enum ExercisesProgress {
     // All exercises are done.
     AllDone,
-    // The current exercise failed and is still pending.
-    CurrentPending,
     // A new exercise is now pending.
     NewPending,
+    // The current exercise is still pending.
+    CurrentPending,
 }
 
 pub enum StateFileStatus {
@@ -34,29 +41,12 @@ pub enum StateFileStatus {
     NotRead,
 }
 
-// Parses parts of the output of `cargo metadata`.
+#[derive(Clone, Copy)]
-#[derive(Deserialize)]
+pub enum CheckProgress {
-struct CargoMetadata {
+    None,
-    target_directory: PathBuf,
+    Checking,
-}
+    Done,
-
+    Pending,
-pub fn parse_target_dir() -> Result<PathBuf> {
-    // Get the target directory from Cargo.
-    let metadata_output = Command::new("cargo")
-        .arg("metadata")
-        .arg("-q")
-        .arg("--format-version")
-        .arg("1")
-        .arg("--no-deps")
-        .stdin(Stdio::null())
-        .stderr(Stdio::inherit())
-        .output()
-        .context(CARGO_METADATA_ERR)?
-        .stdout;
-
-    serde_json::de::from_slice::<CargoMetadata>(&metadata_output)
-        .context("Failed to read the field `target_directory` from the `cargo metadata` output")
-        .map(|metadata| metadata.target_directory)
 }
 
 pub struct AppState {
@@ -65,67 +55,32 @@ pub struct AppState {
     // Caches the number of done exercises to avoid iterating over all exercises every time.
     n_done: u16,
     final_message: String,
+    state_file: File,
     // Preallocated buffer for reading and writing the state file.
     file_buf: Vec<u8>,
     official_exercises: bool,
-    // Cargo's target directory.
+    cmd_runner: CmdRunner,
-    target_dir: PathBuf,
+    emit_file_links: bool,
 }
 
 impl AppState {
-    // Update the app state from the state file.
-    fn update_from_file(&mut self) -> StateFileStatus {
-        self.file_buf.clear();
-        self.n_done = 0;
-
-        if File::open(STATE_FILE_NAME)
-            .and_then(|mut file| file.read_to_end(&mut self.file_buf))
-            .is_err()
-        {
-            return StateFileStatus::NotRead;
-        }
-
-        // See `Self::write` for more information about the file format.
-        let mut lines = self.file_buf.split(|c| *c == b'\n').skip(2);
-
-        let Some(current_exercise_name) = lines.next() else {
-            return StateFileStatus::NotRead;
-        };
-
-        if current_exercise_name.is_empty() || lines.next().is_none() {
-            return StateFileStatus::NotRead;
-        }
-
-        let mut done_exercises = hashbrown::HashSet::with_capacity(self.exercises.len());
-
-        for done_exerise_name in lines {
-            if done_exerise_name.is_empty() {
-                break;
-            }
-            done_exercises.insert(done_exerise_name);
-        }
-
-        for (ind, exercise) in self.exercises.iter_mut().enumerate() {
-            if done_exercises.contains(exercise.name.as_bytes()) {
-                exercise.done = true;
-                self.n_done += 1;
-            }
-
-            if exercise.name.as_bytes() == current_exercise_name {
-                self.current_exercise_ind = ind;
-            }
-        }
-
-        StateFileStatus::Read
-    }
-
     pub fn new(
         exercise_infos: Vec<ExerciseInfo>,
         final_message: String,
     ) -> Result<(Self, StateFileStatus)> {
-        let target_dir = parse_target_dir()?;
+        let cmd_runner = CmdRunner::build()?;
+        let mut state_file = OpenOptions::new()
+            .create(true)
+            .read(true)
+            .write(true)
+            .truncate(false)
+            .open(STATE_FILE_NAME)
+            .with_context(|| {
+                format!("Failed to open or create the state file {STATE_FILE_NAME}")
+            })?;
 
-        let exercises = exercise_infos
+        let dir_canonical_path = term::canonicalize("exercises");
+        let mut exercises = exercise_infos
             .into_iter()
             .map(|exercise_info| {
                 // Leaking to be able to borrow in the watch mode `Table`.
@@ -134,33 +89,100 @@ impl AppState {
                 let path = exercise_info.path().leak();
                 let name = exercise_info.name.leak();
                 let dir = exercise_info.dir.map(|dir| &*dir.leak());
+                let hint = exercise_info.hint.leak().trim_ascii();
 
-                let hint = exercise_info.hint.trim().to_owned();
+                let canonical_path = dir_canonical_path.as_deref().map(|dir_canonical_path| {
+                    let mut canonical_path;
+                    if let Some(dir) = dir {
+                        canonical_path = String::with_capacity(
+                            2 + dir_canonical_path.len() + dir.len() + name.len(),
+                        );
+                        canonical_path.push_str(dir_canonical_path);
+                        canonical_path.push_str(MAIN_SEPARATOR_STR);
+                        canonical_path.push_str(dir);
+                    } else {
+                        canonical_path =
+                            String::with_capacity(1 + dir_canonical_path.len() + name.len());
+                        canonical_path.push_str(dir_canonical_path);
+                    }
+
+                    canonical_path.push_str(MAIN_SEPARATOR_STR);
+                    canonical_path.push_str(name);
+                    canonical_path.push_str(".rs");
+                    canonical_path
+                });
 
                 Exercise {
                     dir,
                     name,
                     path,
+                    canonical_path,
                     test: exercise_info.test,
                     strict_clippy: exercise_info.strict_clippy,
                     hint,
-                    // Updated in `Self::update_from_file`.
+                    // Updated below.
                     done: false,
                 }
             })
             .collect::<Vec<_>>();
 
-        let mut slf = Self {
+        let mut current_exercise_ind = 0;
-            current_exercise_ind: 0,
+        let mut n_done = 0;
-            exercises,
+        let mut file_buf = Vec::with_capacity(2048);
-            n_done: 0,
+        let state_file_status = 'block: {
-            final_message,
+            if state_file.read_to_end(&mut file_buf).is_err() {
-            file_buf: Vec::with_capacity(2048),
+                break 'block StateFileStatus::NotRead;
-            official_exercises: !Path::new("info.toml").exists(),
+            }
-            target_dir,
+
+            // See `Self::write` for more information about the file format.
+            let mut lines = file_buf.split(|c| *c == b'\n').skip(2);
+
+            let Some(current_exercise_name) = lines.next() else {
+                break 'block StateFileStatus::NotRead;
+            };
+
+            if current_exercise_name.is_empty() || lines.next().is_none() {
+                break 'block StateFileStatus::NotRead;
+            }
+
+            let mut done_exercises = HashSet::with_capacity(exercises.len());
+
+            for done_exercise_name in lines {
+                if done_exercise_name.is_empty() {
+                    break;
+                }
+                done_exercises.insert(done_exercise_name);
+            }
+
+            for (ind, exercise) in exercises.iter_mut().enumerate() {
+                if done_exercises.contains(exercise.name.as_bytes()) {
+                    exercise.done = true;
+                    n_done += 1;
+                }
+
+                if exercise.name.as_bytes() == current_exercise_name {
+                    current_exercise_ind = ind;
+                }
+            }
+
+            StateFileStatus::Read
         };
 
-        let state_file_status = slf.update_from_file();
+        file_buf.clear();
+        file_buf.extend_from_slice(STATE_FILE_HEADER);
+
+        let slf = Self {
+            current_exercise_ind,
+            exercises,
+            n_done,
+            final_message,
+            state_file,
+            file_buf,
+            official_exercises: !Path::new("info.toml").exists(),
+            cmd_runner,
+            // VS Code has its own file link handling
+            emit_file_links: env::var_os("TERM_PROGRAM").is_none_or(|v| v != "vscode"),
+        };
 
         Ok((slf, state_file_status))
     }
@@ -180,14 +202,24 @@ impl AppState {
         self.n_done
     }
 
+    #[inline]
+    pub fn n_pending(&self) -> u16 {
+        self.exercises.len() as u16 - self.n_done
+    }
+
     #[inline]
     pub fn current_exercise(&self) -> &Exercise {
         &self.exercises[self.current_exercise_ind]
     }
 
     #[inline]
-    pub fn target_dir(&self) -> &Path {
+    pub fn cmd_runner(&self) -> &CmdRunner {
-        &self.target_dir
+        &self.cmd_runner
+    }
+
+    #[inline]
+    pub fn emit_file_links(&self) -> bool {
+        self.emit_file_links
     }
 
     // Write the state file.
@@ -199,10 +231,8 @@ impl AppState {
     // - The fourth line is an empty line.
     // - All remaining lines are the names of done exercises.
     fn write(&mut self) -> Result<()> {
-        self.file_buf.clear();
+        self.file_buf.truncate(STATE_FILE_HEADER.len());
 
-        self.file_buf
-            .extend_from_slice(b"DON'T EDIT THIS FILE!\n\n");
         self.file_buf
             .extend_from_slice(self.current_exercise().name.as_bytes());
         self.file_buf.push(b'\n');
@@ -214,7 +244,14 @@ impl AppState {
             }
         }
 
-        fs::write(STATE_FILE_NAME, &self.file_buf)
+        self.state_file
+            .rewind()
+            .with_context(|| format!("Failed to rewind the state file {STATE_FILE_NAME}"))?;
+        self.state_file
+            .set_len(0)
+            .with_context(|| format!("Failed to truncate the state file {STATE_FILE_NAME}"))?;
+        self.state_file
+            .write_all(&self.file_buf)
             .with_context(|| format!("Failed to write the state file {STATE_FILE_NAME}"))?;
 
         Ok(())
@@ -246,15 +283,31 @@ impl AppState {
         self.write()
     }
 
-    pub fn set_pending(&mut self, exercise_ind: usize) -> Result<()> {
+    // Set the status of an exercise without saving. Returns `true` if the
+    // status actually changed (and thus needs saving later).
+    pub fn set_status(&mut self, exercise_ind: usize, done: bool) -> Result<bool> {
         let exercise = self
             .exercises
             .get_mut(exercise_ind)
             .context(BAD_INDEX_ERR)?;
 
-        if exercise.done {
+        if exercise.done == done {
-            exercise.done = false;
+            return Ok(false);
+        }
+
+        exercise.done = done;
+        if done {
+            self.n_done += 1;
+        } else {
             self.n_done -= 1;
+        }
+
+        Ok(true)
+    }
+
+    // Set the status of an exercise to "pending" and save.
+    pub fn set_pending(&mut self, exercise_ind: usize) -> Result<()> {
+        if self.set_status(exercise_ind, false)? {
             self.write()?;
         }
 
@@ -262,7 +315,7 @@ impl AppState {
     }
 
     // Official exercises: Dump the original file from the binary.
-    // Third-party exercises: Reset the exercise file with `git stash`.
+    // Community exercises: Reset the exercise file with `git stash`.
     fn reset(&self, exercise_ind: usize, path: &str) -> Result<()> {
         if self.official_exercises {
             return EMBEDDED_FILES
@@ -298,6 +351,7 @@ impl AppState {
         Ok(exercise.path)
     }
 
+    // Reset the exercise by index and return its name.
     pub fn reset_exercise_by_ind(&mut self, exercise_ind: usize) -> Result<&'static str> {
         if exercise_ind >= self.exercises.len() {
             bail!(BAD_INDEX_ERR);
@@ -307,36 +361,33 @@ impl AppState {
         let exercise = &self.exercises[exercise_ind];
         self.reset(exercise_ind, exercise.path)?;
 
-        Ok(exercise.path)
+        Ok(exercise.name)
     }
 
     // Return the index of the next pending exercise or `None` if all exercises are done.
     fn next_pending_exercise_ind(&self) -> Option<usize> {
-        if self.current_exercise_ind == self.exercises.len() - 1 {
+        let next_ind = self.current_exercise_ind + 1;
-            // The last exercise is done.
+        self.exercises
-            // Search for exercises not done from the start.
+            // If the exercise done isn't the last, search for pending exercises after it.
-            return self.exercises[..self.current_exercise_ind]
+            .get(next_ind..)
-                .iter()
+            .and_then(|later_exercises| {
-                .position(|exercise| !exercise.done);
+                later_exercises
-        }
+                    .iter()
-
+                    .position(|exercise| !exercise.done)
-        // The done exercise isn't the last one.
+                    .map(|ind| next_ind + ind)
-        // Search for a pending exercise after the current one and then from the start.
+            })
-        match self.exercises[self.current_exercise_ind + 1..]
+            // Search from the start.
-            .iter()
+            .or_else(|| {
-            .position(|exercise| !exercise.done)
+                self.exercises[..self.current_exercise_ind]
-        {
+                    .iter()
-            Some(ind) => Some(self.current_exercise_ind + 1 + ind),
+                    .position(|exercise| !exercise.done)
-            None => self.exercises[..self.current_exercise_ind]
+            })
-                .iter()
-                .position(|exercise| !exercise.done),
-        }
     }
 
-    /// Official exercises: Dump the solution file form the binary and return its path.
+    /// Official exercises: Dump the solution file from the binary and return its path.
-    /// Third-party exercises: Check if a solution file exists and return its path in that case.
+    /// Community exercises: Check if a solution file exists and return its path in that case.
     pub fn current_solution_path(&self) -> Result<Option<String>> {
-        if DEBUG_PROFILE {
+        if cfg!(debug_assertions) {
             return Ok(None);
         }
 
@@ -347,24 +398,135 @@ impl AppState {
                 .write_solution_to_disk(self.current_exercise_ind, current_exercise.name)
                 .map(Some)
         } else {
-            let solution_path = if let Some(dir) = current_exercise.dir {
+            let sol_path = current_exercise.sol_path();
-                format!("solutions/{dir}/{}.rs", current_exercise.name)
-            } else {
-                format!("solutions/{}.rs", current_exercise.name)
-            };
 
-            if Path::new(&solution_path).exists() {
+            if Path::new(&sol_path).exists() {
-                return Ok(Some(solution_path));
+                return Ok(Some(sol_path));
             }
 
             Ok(None)
         }
     }
 
+    fn check_all_exercises_impl(&mut self, stdout: &mut StdoutLock) -> Result<Option<usize>> {
+        let term_width = terminal::size()
+            .context("Failed to get the terminal size")?
+            .0;
+        let mut progress_visualizer = CheckProgressVisualizer::build(stdout, term_width)?;
+
+        let next_exercise_ind = AtomicUsize::new(0);
+        let mut progresses = vec![CheckProgress::None; self.exercises.len()];
+
+        thread::scope(|s| {
+            let (exercise_progress_sender, exercise_progress_receiver) = mpsc::channel();
+            let n_threads = thread::available_parallelism()
+                .map_or(DEFAULT_CHECK_PARALLELISM, |count| count.get());
+
+            for _ in 0..n_threads {
+                let exercise_progress_sender = exercise_progress_sender.clone();
+                let next_exercise_ind = &next_exercise_ind;
+                let slf = &self;
+                thread::Builder::new()
+                    .spawn_scoped(s, move || {
+                        loop {
+                            let exercise_ind = next_exercise_ind.fetch_add(1, Relaxed);
+                            let Some(exercise) = slf.exercises.get(exercise_ind) else {
+                                // No more exercises.
+                                break;
+                            };
+
+                            if exercise_progress_sender
+                                .send((exercise_ind, CheckProgress::Checking))
+                                .is_err()
+                            {
+                                break;
+                            };
+
+                            let success = exercise.run_exercise(None, &slf.cmd_runner);
+                            let progress = match success {
+                                Ok(true) => CheckProgress::Done,
+                                Ok(false) => CheckProgress::Pending,
+                                Err(_) => CheckProgress::None,
+                            };
+
+                            if exercise_progress_sender
+                                .send((exercise_ind, progress))
+                                .is_err()
+                            {
+                                break;
+                            }
+                        }
+                    })
+                    .context("Failed to spawn a thread to check all exercises")?;
+            }
+
+            // Drop this sender to detect when the last thread is done.
+            drop(exercise_progress_sender);
+
+            while let Ok((exercise_ind, progress)) = exercise_progress_receiver.recv() {
+                progresses[exercise_ind] = progress;
+                progress_visualizer.update(&progresses)?;
+            }
+
+            Ok::<_, Error>(())
+        })?;
+
+        let mut first_pending_exercise_ind = None;
+        for exercise_ind in 0..progresses.len() {
+            match progresses[exercise_ind] {
+                CheckProgress::Done => {
+                    self.set_status(exercise_ind, true)?;
+                }
+                CheckProgress::Pending => {
+                    self.set_status(exercise_ind, false)?;
+                    if first_pending_exercise_ind.is_none() {
+                        first_pending_exercise_ind = Some(exercise_ind);
+                    }
+                }
+                CheckProgress::None | CheckProgress::Checking => {
+                    // If we got an error while checking all exercises in parallel,
+                    // it could be because we exceeded the limit of open file descriptors.
+                    // Therefore, try running exercises with errors sequentially.
+                    progresses[exercise_ind] = CheckProgress::Checking;
+                    progress_visualizer.update(&progresses)?;
+
+                    let exercise = &self.exercises[exercise_ind];
+                    let success = exercise.run_exercise(None, &self.cmd_runner)?;
+                    if success {
+                        progresses[exercise_ind] = CheckProgress::Done;
+                    } else {
+                        progresses[exercise_ind] = CheckProgress::Pending;
+                        if first_pending_exercise_ind.is_none() {
+                            first_pending_exercise_ind = Some(exercise_ind);
+                        }
+                    }
+                    self.set_status(exercise_ind, success)?;
+                    progress_visualizer.update(&progresses)?;
+                }
+            }
+        }
+
+        self.write()?;
+
+        Ok(first_pending_exercise_ind)
+    }
+
+    // Return the exercise index of the first pending exercise found.
+    pub fn check_all_exercises(&mut self, stdout: &mut StdoutLock) -> Result<Option<usize>> {
+        stdout.queue(cursor::Hide)?;
+        let res = self.check_all_exercises_impl(stdout);
+        stdout.queue(cursor::Show)?;
+
+        res
+    }
+
     /// Mark the current exercise as done and move on to the next pending exercise if one exists.
     /// If all exercises are marked as done, run all of them to make sure that they are actually
     /// done. If an exercise which is marked as done fails, mark it as pending and continue on it.
-    pub fn done_current_exercise(&mut self, writer: &mut StdoutLock) -> Result<ExercisesProgress> {
+    pub fn done_current_exercise<const CLEAR_BEFORE_FINAL_CHECK: bool>(
+        &mut self,
+        stdout: &mut StdoutLock,
+    ) -> Result<ExercisesProgress> {
         let exercise = &mut self.exercises[self.current_exercise_ind];
         if !exercise.done {
             exercise.done = true;
@@ -373,62 +535,42 @@ impl AppState {
 
         if let Some(ind) = self.next_pending_exercise_ind() {
             self.set_current_exercise_ind(ind)?;
+            return Ok(ExercisesProgress::NewPending);
+        }
+
+        if CLEAR_BEFORE_FINAL_CHECK {
+            clear_terminal(stdout)?;
+        } else {
+            stdout.write_all(b"\n")?;
+        }
+
+        if let Some(first_pending_exercise_ind) = self.check_all_exercises(stdout)? {
+            self.set_current_exercise_ind(first_pending_exercise_ind)?;
 
             return Ok(ExercisesProgress::NewPending);
         }
 
-        writer.write_all(RERUNNING_ALL_EXERCISES_MSG)?;
+        self.render_final_message(stdout)?;
-
-        let mut output = Vec::with_capacity(OUTPUT_CAPACITY);
-        for (exercise_ind, exercise) in self.exercises().iter().enumerate() {
-            write!(writer, "Running {exercise} ... ")?;
-            writer.flush()?;
-
-            let success = exercise.run_exercise(&mut output, &self.target_dir)?;
-            if !success {
-                writeln!(writer, "{}\n", "FAILED".red())?;
-
-                self.current_exercise_ind = exercise_ind;
-
-                // No check if the exercise is done before setting it to pending
-                // because no pending exercise was found.
-                self.exercises[exercise_ind].done = false;
-                self.n_done -= 1;
-
-                self.write()?;
-
-                return Ok(ExercisesProgress::NewPending);
-            }
-
-            writeln!(writer, "{}", "ok".green())?;
-        }
-
-        // Write that the last exercise is done.
-        self.write()?;
-
-        clear_terminal(writer)?;
-        writer.write_all(FENISH_LINE.as_bytes())?;
-
-        let final_message = self.final_message.trim();
-        if !final_message.is_empty() {
-            writer.write_all(final_message.as_bytes())?;
-            writer.write_all(b"\n")?;
-        }
 
         Ok(ExercisesProgress::AllDone)
     }
+
+    pub fn render_final_message(&self, stdout: &mut StdoutLock) -> Result<()> {
+        clear_terminal(stdout)?;
+        stdout.write_all(FENISH_LINE.as_bytes())?;
+
+        let final_message = self.final_message.trim_ascii();
+        if !final_message.is_empty() {
+            stdout.write_all(final_message.as_bytes())?;
+            stdout.write_all(b"\n")?;
+        }
+
+        Ok(())
+    }
 }
 
-const CARGO_METADATA_ERR: &str = "Failed to run the command `cargo metadata …`
+const BAD_INDEX_ERR: &str = "The current exercise index is higher than the number of exercises";
-Did you already install Rust?
+const STATE_FILE_HEADER: &[u8] = b"DON'T EDIT THIS FILE!\n\n";
-Try running `cargo --version` to diagnose the problem.";
-
-const RERUNNING_ALL_EXERCISES_MSG: &[u8] = b"
-All exercises seem to be done.
-Recompiling and running all exercises to make sure that all of them are actually done.
-
-";
-
 const FENISH_LINE: &str = "+----------------------------------------------------+
 |          You made it to the Fe-nish line!          |
 +--------------------------  ------------------------+
@@ -460,9 +602,10 @@ mod tests {
             dir: None,
             name: "0",
             path: "exercises/0.rs",
+            canonical_path: None,
             test: false,
             strict_clippy: false,
-            hint: String::new(),
+            hint: "",
             done: false,
         }
     }
@@ -474,9 +617,11 @@ mod tests {
             exercises: vec![dummy_exercise(), dummy_exercise(), dummy_exercise()],
             n_done: 0,
             final_message: String::new(),
+            state_file: tempfile::tempfile().unwrap(),
             file_buf: Vec::new(),
             official_exercises: true,
-            target_dir: PathBuf::new(),
+            cmd_runner: CmdRunner::build().unwrap(),
+            emit_file_links: true,
         };
 
         let mut assert = |done: [bool; 3], expected: [Option<usize>; 3]| {

src/cargo_toml.rs

@@ -1,7 +1,7 @@
 use anyhow::{Context, Result};
 use std::path::Path;
 
-use crate::info_file::ExerciseInfo;
+use crate::{exercise::RunnableExercise, info_file::ExerciseInfo};
 
 /// Initial capacity of the bins buffer.
 pub const BINS_BUFFER_CAPACITY: usize = 1 << 14;
@@ -74,13 +74,13 @@ pub fn updated_cargo_toml(
     let (bins_start_ind, bins_end_ind) = bins_start_end_ind(current_cargo_toml)?;
 
     let mut updated_cargo_toml = Vec::with_capacity(BINS_BUFFER_CAPACITY);
-    updated_cargo_toml.extend_from_slice(current_cargo_toml[..bins_start_ind].as_bytes());
+    updated_cargo_toml.extend_from_slice(&current_cargo_toml.as_bytes()[..bins_start_ind]);
     append_bins(
         &mut updated_cargo_toml,
         exercise_infos,
         exercise_path_prefix,
     );
-    updated_cargo_toml.extend_from_slice(current_cargo_toml[bins_end_ind..].as_bytes());
+    updated_cargo_toml.extend_from_slice(&current_cargo_toml.as_bytes()[bins_end_ind..]);
 
     Ok(updated_cargo_toml)
 }
@@ -134,7 +134,14 @@ mod tests {
         );
 
         assert_eq!(
-            updated_cargo_toml(&exercise_infos, "abc\nbin = [xxx]\n123", b"../").unwrap(),
+            updated_cargo_toml(
+                &exercise_infos,
+                "abc\n\
+                 bin = [xxx]\n\
+                 123",
+                b"../"
+            )
+            .unwrap(),
             br#"abc
 bin = [
   { name = "1", path = "../exercises/1.rs" },

src/cmd.rs

@@ -1,30 +1,44 @@
-use anyhow::{Context, Result};
+use anyhow::{Context, Result, bail};
-use std::{io::Read, path::Path, process::Command};
+use serde::Deserialize;
+use std::{
+    io::{Read, pipe},
+    path::PathBuf,
+    process::{Command, Stdio},
+};
 
 /// Run a command with a description for a possible error and append the merged stdout and stderr.
 /// The boolean in the returned `Result` is true if the command's exit status is success.
-pub fn run_cmd(mut cmd: Command, description: &str, output: &mut Vec<u8>) -> Result<bool> {
+fn run_cmd(mut cmd: Command, description: &str, output: Option<&mut Vec<u8>>) -> Result<bool> {
-    let (mut reader, writer) = os_pipe::pipe()
+    let spawn = |mut cmd: Command| {
-        .with_context(|| format!("Failed to create a pipe to run the command `{description}``"))?;
+        // NOTE: The closure drops `cmd` which prevents a pipe deadlock.
+        cmd.stdin(Stdio::null())
+            .spawn()
+            .with_context(|| format!("Failed to run the command `{description}`"))
+    };
 
-    let writer_clone = writer.try_clone().with_context(|| {
+    let mut handle = if let Some(output) = output {
-        format!("Failed to clone the pipe writer for the command `{description}`")
+        let (mut reader, writer) = pipe().with_context(|| {
-    })?;
+            format!("Failed to create a pipe to run the command `{description}``")
+        })?;
 
-    let mut handle = cmd
+        let writer_clone = writer.try_clone().with_context(|| {
-        .stdout(writer_clone)
+            format!("Failed to clone the pipe writer for the command `{description}`")
-        .stderr(writer)
+        })?;
-        .spawn()
-        .with_context(|| format!("Failed to run the command `{description}`"))?;
 
-    // Prevent pipe deadlock.
+        cmd.stdout(writer_clone).stderr(writer);
-    drop(cmd);
+        let handle = spawn(cmd)?;
 
-    reader
+        reader
-        .read_to_end(output)
+            .read_to_end(output)
-        .with_context(|| format!("Failed to read the output of the command `{description}`"))?;
+            .with_context(|| format!("Failed to read the output of the command `{description}`"))?;
 
-    output.push(b'\n');
+        output.push(b'\n');
+
+        handle
+    } else {
+        cmd.stdout(Stdio::null()).stderr(Stdio::null());
+        spawn(cmd)?
+    };
 
     handle
         .wait()
@@ -32,50 +46,106 @@ pub fn run_cmd(mut cmd: Command, description: &str, output: &mut Vec<u8>) -> Res
         .map(|status| status.success())
 }
 
-pub struct CargoCmd<'a> {
+// Parses parts of the output of `cargo metadata`.
-    pub subcommand: &'a str,
+#[derive(Deserialize)]
-    pub args: &'a [&'a str],
+struct CargoMetadata {
-    pub bin_name: &'a str,
+    target_directory: PathBuf,
-    pub description: &'a str,
-    /// RUSTFLAGS="-A warnings"
-    pub hide_warnings: bool,
-    /// Added as `--target-dir` if `Self::dev` is true.
-    pub target_dir: &'a Path,
-    /// The output buffer to append the merged stdout and stderr.
-    pub output: &'a mut Vec<u8>,
-    /// true while developing Rustlings.
-    pub dev: bool,
 }
 
-impl<'a> CargoCmd<'a> {
+pub struct CmdRunner {
-    /// Run `cargo SUBCOMMAND --bin EXERCISE_NAME … ARGS`.
+    target_dir: PathBuf,
-    pub fn run(&mut self) -> Result<bool> {
+}
+
+impl CmdRunner {
+    pub fn build() -> Result<Self> {
+        // Get the target directory from Cargo.
+        let metadata_output = Command::new("cargo")
+            .arg("metadata")
+            .arg("-q")
+            .arg("--format-version")
+            .arg("1")
+            .arg("--no-deps")
+            .stdin(Stdio::null())
+            .stderr(Stdio::inherit())
+            .output()
+            .context(CARGO_METADATA_ERR)?;
+
+        if !metadata_output.status.success() {
+            bail!("The command `cargo metadata …` failed. Are you in the `rustlings/` directory?");
+        }
+
+        let metadata: CargoMetadata = serde_json::de::from_slice(&metadata_output.stdout)
+            .context(
+                "Failed to read the field `target_directory` from the output of the command `cargo metadata …`",
+            )?;
+
+        Ok(Self {
+            target_dir: metadata.target_directory,
+        })
+    }
+
+    pub fn cargo<'out>(
+        &self,
+        subcommand: &str,
+        bin_name: &str,
+        output: Option<&'out mut Vec<u8>>,
+    ) -> CargoSubcommand<'out> {
         let mut cmd = Command::new("cargo");
-        cmd.arg(self.subcommand);
+        cmd.arg(subcommand).arg("-q").arg("--bin").arg(bin_name);
 
         // A hack to make `cargo run` work when developing Rustlings.
-        if self.dev {
+        #[cfg(debug_assertions)]
-            cmd.arg("--manifest-path")
+        cmd.arg("--manifest-path")
-                .arg("dev/Cargo.toml")
+            .arg("dev/Cargo.toml")
-                .arg("--target-dir")
+            .arg("--target-dir")
-                .arg(self.target_dir);
+            .arg(&self.target_dir);
+
+        if output.is_some() {
+            cmd.arg("--color").arg("always");
         }
 
-        cmd.arg("--color")
+        CargoSubcommand { cmd, output }
-            .arg("always")
+    }
-            .arg("-q")
-            .arg("--bin")
-            .arg(self.bin_name)
-            .args(self.args);
 
-        if self.hide_warnings {
+    /// The boolean in the returned `Result` is true if the command's exit status is success.
-            cmd.env("RUSTFLAGS", "-A warnings");
+    pub fn run_debug_bin(&self, bin_name: &str, output: Option<&mut Vec<u8>>) -> Result<bool> {
-        }
+        // 7 = "/debug/".len()
+        let mut bin_path =
+            PathBuf::with_capacity(self.target_dir.as_os_str().len() + 7 + bin_name.len());
+        bin_path.push(&self.target_dir);
+        bin_path.push("debug");
+        bin_path.push(bin_name);
 
-        run_cmd(cmd, self.description, self.output)
+        run_cmd(Command::new(&bin_path), &bin_path.to_string_lossy(), output)
     }
 }
 
+pub struct CargoSubcommand<'out> {
+    cmd: Command,
+    output: Option<&'out mut Vec<u8>>,
+}
+
+impl CargoSubcommand<'_> {
+    #[inline]
+    pub fn args<'arg, I>(&mut self, args: I) -> &mut Self
+    where
+        I: IntoIterator<Item = &'arg str>,
+    {
+        self.cmd.args(args);
+        self
+    }
+
+    /// The boolean in the returned `Result` is true if the command's exit status is success.
+    #[inline]
+    pub fn run(self, description: &str) -> Result<bool> {
+        run_cmd(self.cmd, description, self.output)
+    }
+}
+
+const CARGO_METADATA_ERR: &str = "Failed to run the command `cargo metadata …`
+Did you already install Rust?
+Try running `cargo --version` to diagnose the problem.";
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -86,7 +156,7 @@ mod tests {
         cmd.arg("Hello");
 
         let mut output = Vec::with_capacity(8);
-        run_cmd(cmd, "echo …", &mut output).unwrap();
+        run_cmd(cmd, "echo …", Some(&mut output)).unwrap();
 
         assert_eq!(output, b"Hello\n\n");
     }

src/dev.rs

@@ -1,16 +1,14 @@
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result, bail};
 use clap::Subcommand;
 use std::path::PathBuf;
 
-use crate::DEBUG_PROFILE;
-
 mod check;
 mod new;
 mod update;
 
 #[derive(Subcommand)]
 pub enum DevCommands {
-    /// Create a new project for third-party Rustlings exercises
+    /// Create a new project for community exercises
     New {
         /// The path to create the project in
         path: PathBuf,
@@ -32,7 +30,7 @@ impl DevCommands {
     pub fn run(self) -> Result<()> {
         match self {
             Self::New { path, no_git } => {
-                if DEBUG_PROFILE {
+                if cfg!(debug_assertions) {
                     bail!("Disabled in the debug build");
                 }
 

src/dev/check.rs

@@ -1,56 +1,65 @@
-use anyhow::{anyhow, bail, Context, Result};
+use anyhow::{Context, Error, Result, anyhow, bail};
 use std::{
     cmp::Ordering,
-    fs::{self, read_dir, OpenOptions},
+    collections::HashSet,
+    fs::{self, OpenOptions, read_dir},
     io::{self, Read, Write},
     path::{Path, PathBuf},
-    sync::{
+    process::{Command, Stdio},
-        atomic::{self, AtomicBool},
-        Mutex,
-    },
     thread,
 };
 
 use crate::{
-    app_state::parse_target_dir,
+    CURRENT_FORMAT_VERSION,
-    cargo_toml::{append_bins, bins_start_end_ind, BINS_BUFFER_CAPACITY},
+    cargo_toml::{BINS_BUFFER_CAPACITY, append_bins, bins_start_end_ind},
-    exercise::{RunnableExercise, OUTPUT_CAPACITY},
+    cmd::CmdRunner,
+    exercise::{OUTPUT_CAPACITY, RunnableExercise},
     info_file::{ExerciseInfo, InfoFile},
-    CURRENT_FORMAT_VERSION, DEBUG_PROFILE,
+    term::ProgressCounter,
 };
 
+const MAX_N_EXERCISES: usize = 999;
+const MAX_EXERCISE_NAME_LEN: usize = 32;
+
 // Find a char that isn't allowed in the exercise's `name` or `dir`.
 fn forbidden_char(input: &str) -> Option<char> {
     input.chars().find(|c| !c.is_alphanumeric() && *c != '_')
 }
 
-// Check that the Cargo.toml file is up-to-date.
+// Check that the `Cargo.toml` file is up-to-date.
 fn check_cargo_toml(
     exercise_infos: &[ExerciseInfo],
-    current_cargo_toml: &str,
+    cargo_toml_path: &str,
     exercise_path_prefix: &[u8],
 ) -> Result<()> {
-    let (bins_start_ind, bins_end_ind) = bins_start_end_ind(current_cargo_toml)?;
+    let current_cargo_toml = fs::read_to_string(cargo_toml_path)
+        .with_context(|| format!("Failed to read the file `{cargo_toml_path}`"))?;
+
+    let (bins_start_ind, bins_end_ind) = bins_start_end_ind(&current_cargo_toml)?;
 
     let old_bins = &current_cargo_toml.as_bytes()[bins_start_ind..bins_end_ind];
     let mut new_bins = Vec::with_capacity(BINS_BUFFER_CAPACITY);
     append_bins(&mut new_bins, exercise_infos, exercise_path_prefix);
 
     if old_bins != new_bins {
-        if DEBUG_PROFILE {
+        if cfg!(debug_assertions) {
-            bail!("The file `dev/Cargo.toml` is outdated. Please run `cargo run -- dev update` to update it");
+            bail!(
+                "The file `dev/Cargo.toml` is outdated. Run `cargo dev update` to update it. Then run `cargo run -- dev check` again"
+            );
         }
 
-        bail!("The file `Cargo.toml` is outdated. Please run `rustlings dev update` to update it");
+        bail!(
+            "The file `Cargo.toml` is outdated. Run `rustlings dev update` to update it. Then run `rustlings dev check` again"
+        );
     }
 
     Ok(())
 }
 
 // Check the info of all exercises and return their paths in a set.
-fn check_info_file_exercises(info_file: &InfoFile) -> Result<hashbrown::HashSet<PathBuf>> {
+fn check_info_file_exercises(info_file: &InfoFile) -> Result<HashSet<PathBuf>> {
-    let mut names = hashbrown::HashSet::with_capacity(info_file.exercises.len());
+    let mut names = HashSet::with_capacity(info_file.exercises.len());
-    let mut paths = hashbrown::HashSet::with_capacity(info_file.exercises.len());
+    let mut paths = HashSet::with_capacity(info_file.exercises.len());
 
     let mut file_buf = String::with_capacity(1 << 14);
     for exercise_info in &info_file.exercises {
@@ -58,6 +67,11 @@ fn check_info_file_exercises(info_file: &InfoFile) -> Result<hashbrown::HashSet<
         if name.is_empty() {
             bail!("Found an empty exercise name in `info.toml`");
         }
+        if name.len() > MAX_EXERCISE_NAME_LEN {
+            bail!(
+                "The length of the exercise name `{name}` is bigger than the maximum {MAX_EXERCISE_NAME_LEN}"
+            );
+        }
         if let Some(c) = forbidden_char(name) {
             bail!("Char `{c}` in the exercise name `{name}` is not allowed");
         }
@@ -71,8 +85,10 @@ fn check_info_file_exercises(info_file: &InfoFile) -> Result<hashbrown::HashSet<
             }
         }
 
-        if exercise_info.hint.trim().is_empty() {
+        if exercise_info.hint.trim_ascii().is_empty() {
-            bail!("The exercise `{name}` has an empty hint. Please provide a hint or at least tell the user why a hint isn't needed for this exercise");
+            bail!(
+                "The exercise `{name}` has an empty hint. Please provide a hint or at least tell the user why a hint isn't needed for this exercise"
+            );
         }
 
         if !names.insert(name) {
@@ -89,15 +105,30 @@ fn check_info_file_exercises(info_file: &InfoFile) -> Result<hashbrown::HashSet<
             .with_context(|| format!("Failed to read the file {path}"))?;
 
         if !file_buf.contains("fn main()") {
-            bail!("The `main` function is missing in the file `{path}`.\nCreate at least an empty `main` function to avoid language server errors");
+            bail!(
+                "The `main` function is missing in the file `{path}`.\n\
+                 Create at least an empty `main` function to avoid language server errors"
+            );
         }
 
         if !file_buf.contains("// TODO") {
-            bail!("Didn't find any `// TODO` comment in the file `{path}`.\nYou need to have at least one such comment to guide the user.");
+            bail!(
+                "Didn't find any `// TODO` comment in the file `{path}`.\n\
+                 You need to have at least one such comment to guide the user."
+            );
         }
 
-        if !exercise_info.test && file_buf.contains("#[test]") {
+        let contains_tests = file_buf.contains("#[test]\n");
-            bail!("The file `{path}` contains tests annotated with `#[test]` but the exercise `{name}` has `test = false` in the `info.toml` file");
+        if exercise_info.test {
+            if !contains_tests {
+                bail!(
+                    "The file `{path}` doesn't contain any tests. If you don't want to add tests to this exercise, set `test = false` for this exercise in the `info.toml` file"
+                );
+            }
+        } else if contains_tests {
+            bail!(
+                "The file `{path}` contains tests annotated with `#[test]` but the exercise `{name}` has `test = false` in the `info.toml` file"
+            );
         }
 
         file_buf.clear();
@@ -111,12 +142,12 @@ fn check_info_file_exercises(info_file: &InfoFile) -> Result<hashbrown::HashSet<
 // Check `dir` for unexpected files.
 // Only Rust files in `allowed_rust_files` and `README.md` files are allowed.
 // Only one level of directory nesting is allowed.
-fn check_unexpected_files(
+fn check_unexpected_files(dir: &str, allowed_rust_files: &HashSet<PathBuf>) -> Result<()> {
-    dir: &str,
-    allowed_rust_files: &hashbrown::HashSet<PathBuf>,
-) -> Result<()> {
     let unexpected_file = |path: &Path| {
-        anyhow!("Found the file `{}`. Only `README.md` and Rust files related to an exercise in `info.toml` are allowed in the `{dir}` directory", path.display())
+        anyhow!(
+            "Found the file `{}`. Only `README.md` and Rust files related to an exercise in `info.toml` are allowed in the `{dir}` directory",
+            path.display()
+        )
     };
 
     for entry in read_dir(dir).with_context(|| format!("Failed to open the `{dir}` directory"))? {
@@ -145,7 +176,10 @@ fn check_unexpected_files(
             let path = entry.path();
 
             if !entry.file_type().unwrap().is_file() {
-                bail!("Found `{}` but expected only files. Only one level of exercise nesting is allowed", path.display());
+                bail!(
+                    "Found `{}` but expected only files. Only one level of exercise nesting is allowed",
+                    path.display()
+                );
             }
 
             let file_name = path.file_name().unwrap();
@@ -162,135 +196,203 @@ fn check_unexpected_files(
     Ok(())
 }
 
-fn check_exercises_unsolved(info_file: &InfoFile, target_dir: &Path) -> Result<()> {
+fn check_exercises_unsolved(
-    let error_occurred = AtomicBool::new(false);
+    info_file: &'static InfoFile,
+    cmd_runner: &'static CmdRunner,
+) -> Result<()> {
+    let mut stdout = io::stdout().lock();
+    stdout.write_all(b"Running all exercises to check that they aren't already solved...\n")?;
 
-    println!(
+    let handles = info_file
-        "Running all exercises to check that they aren't already solved. This may take a while…\n",
+        .exercises
-    );
+        .iter()
-    thread::scope(|s| {
+        .filter_map(|exercise_info| {
-        for exercise_info in &info_file.exercises {
             if exercise_info.skip_check_unsolved {
-                continue;
+                return None;
             }
 
-            s.spawn(|| {
+            Some(
-                let error = |e| {
+                thread::Builder::new()
-                    let mut stderr = io::stderr().lock();
+                    .spawn(|| exercise_info.run_exercise(None, cmd_runner))
-                    stderr.write_all(e).unwrap();
+                    .map(|handle| (exercise_info.name.as_str(), handle)),
-                    stderr.write_all(b"\nProblem with the exercise ").unwrap();
+            )
-                    stderr.write_all(exercise_info.name.as_bytes()).unwrap();
+        })
-                    stderr.write_all(SEPARATOR).unwrap();
+        .collect::<Result<Vec<_>, _>>()
-                    error_occurred.store(true, atomic::Ordering::Relaxed);
+        .context("Failed to spawn a thread to check if an exercise is already solved")?;
-                };
 
-                let mut output = Vec::with_capacity(OUTPUT_CAPACITY);
+    let mut progress_counter = ProgressCounter::new(&mut stdout, handles.len())?;
-                match exercise_info.run_exercise(&mut output, target_dir) {
+
-                    Ok(true) => error(b"Already solved!"),
+    for (exercise_name, handle) in handles {
-                    Ok(false) => (),
+        let Ok(result) = handle.join() else {
-                    Err(e) => error(e.to_string().as_bytes()),
+            bail!("Panic while trying to run the exercise {exercise_name}");
-                }
+        };
-            });
+
+        match result {
+            Ok(true) => {
+                bail!(
+                    "The exercise {exercise_name} is already solved.\n\
+                     {SKIP_CHECK_UNSOLVED_HINT}",
+                )
+            }
+            Ok(false) => (),
+            Err(e) => return Err(e),
         }
-    });
 
-    if error_occurred.load(atomic::Ordering::Relaxed) {
+        progress_counter.increment()?;
-        bail!(CHECK_EXERCISES_UNSOLVED_ERR);
     }
 
     Ok(())
 }
 
-fn check_exercises(info_file: &InfoFile, target_dir: &Path) -> Result<()> {
+fn check_exercises(info_file: &'static InfoFile, cmd_runner: &'static CmdRunner) -> Result<()> {
     match info_file.format_version.cmp(&CURRENT_FORMAT_VERSION) {
-        Ordering::Less => bail!("`format_version` < {CURRENT_FORMAT_VERSION} (supported version)\nPlease migrate to the latest format version"),
+        Ordering::Less => bail!(
-        Ordering::Greater => bail!("`format_version` > {CURRENT_FORMAT_VERSION} (supported version)\nTry updating the Rustlings program"),
+            "`format_version` < {CURRENT_FORMAT_VERSION} (supported version)\n\
+             Please migrate to the latest format version"
+        ),
+        Ordering::Greater => bail!(
+            "`format_version` > {CURRENT_FORMAT_VERSION} (supported version)\n\
+             Try updating the Rustlings program"
+        ),
         Ordering::Equal => (),
     }
 
+    let handle = thread::Builder::new()
+        .spawn(move || check_exercises_unsolved(info_file, cmd_runner))
+        .context("Failed to spawn a thread to check if any exercise is already solved")?;
+
     let info_file_paths = check_info_file_exercises(info_file)?;
     check_unexpected_files("exercises", &info_file_paths)?;
 
-    check_exercises_unsolved(info_file, target_dir)
+    handle.join().unwrap()
 }
 
-fn check_solutions(require_solutions: bool, info_file: &InfoFile, target_dir: &Path) -> Result<()> {
+enum SolutionCheck {
-    let paths = Mutex::new(hashbrown::HashSet::with_capacity(info_file.exercises.len()));
+    Success { sol_path: String },
-    let error_occurred = AtomicBool::new(false);
+    MissingOptional,
+    RunFailure { output: Vec<u8> },
+    Err(Error),
+}
 
-    println!("Running all solutions. This may take a while…\n");
+fn check_solutions(
-    thread::scope(|s| {
+    require_solutions: bool,
-        for exercise_info in &info_file.exercises {
+    info_file: &'static InfoFile,
-            s.spawn(|| {
+    cmd_runner: &'static CmdRunner,
-                let error = |e| {
+) -> Result<()> {
-                    let mut stderr = io::stderr().lock();
+    let mut stdout = io::stdout().lock();
-                    stderr.write_all(e).unwrap();
+    stdout.write_all(b"Running all solutions...\n")?;
-                    stderr
-                        .write_all(b"\nFailed to run the solution of the exercise ")
-                        .unwrap();
-                    stderr.write_all(exercise_info.name.as_bytes()).unwrap();
-                    stderr.write_all(SEPARATOR).unwrap();
-                    error_occurred.store(true, atomic::Ordering::Relaxed);
-                };
 
-                let path = exercise_info.sol_path();
+    let handles = info_file
-                if !Path::new(&path).exists() {
+        .exercises
+        .iter()
+        .map(|exercise_info| {
+            thread::Builder::new().spawn(move || {
+                let sol_path = exercise_info.sol_path();
+                if !Path::new(&sol_path).exists() {
                     if require_solutions {
-                        error(b"Solution missing");
+                        return SolutionCheck::Err(anyhow!(
+                            "The solution of the exercise {} is missing",
+                            exercise_info.name,
+                        ));
                     }
 
-                    // No solution to check.
+                    return SolutionCheck::MissingOptional;
-                    return;
                 }
 
                 let mut output = Vec::with_capacity(OUTPUT_CAPACITY);
-                match exercise_info.run_solution(&mut output, target_dir) {
+                match exercise_info.run_solution(Some(&mut output), cmd_runner) {
-                    Ok(true) => {
+                    Ok(true) => SolutionCheck::Success { sol_path },
-                        paths.lock().unwrap().insert(PathBuf::from(path));
+                    Ok(false) => SolutionCheck::RunFailure { output },
-                    }
+                    Err(e) => SolutionCheck::Err(e),
-                    Ok(false) => error(&output),
-                    Err(e) => error(e.to_string().as_bytes()),
                 }
-            });
+            })
-        }
+        })
-    });
+        .collect::<Result<Vec<_>, _>>()
+        .context("Failed to spawn a thread to check a solution")?;
 
-    if error_occurred.load(atomic::Ordering::Relaxed) {
+    let mut sol_paths = HashSet::with_capacity(info_file.exercises.len());
-        bail!("At least one solution failed. See the output above.");
+    let mut fmt_cmd = Command::new("rustfmt");
+    fmt_cmd
+        .arg("--check")
+        .arg("--edition")
+        .arg("2024")
+        .arg("--color")
+        .arg("always")
+        .stdin(Stdio::null());
+
+    let mut progress_counter = ProgressCounter::new(&mut stdout, handles.len())?;
+
+    for (exercise_info, handle) in info_file.exercises.iter().zip(handles) {
+        let Ok(check_result) = handle.join() else {
+            bail!(
+                "Panic while trying to run the solution of the exercise {}",
+                exercise_info.name,
+            );
+        };
+
+        match check_result {
+            SolutionCheck::Success { sol_path } => {
+                fmt_cmd.arg(&sol_path);
+                sol_paths.insert(PathBuf::from(sol_path));
+            }
+            SolutionCheck::MissingOptional => (),
+            SolutionCheck::RunFailure { output } => {
+                drop(progress_counter);
+                stdout.write_all(&output)?;
+                bail!(
+                    "Running the solution of the exercise {} failed with the error above",
+                    exercise_info.name,
+                );
+            }
+            SolutionCheck::Err(e) => return Err(e),
+        }
+
+        progress_counter.increment()?;
     }
 
-    check_unexpected_files("solutions", &paths.into_inner().unwrap())?;
+    let n_solutions = sol_paths.len();
+    let handle = thread::Builder::new()
+        .spawn(move || check_unexpected_files("solutions", &sol_paths))
+        .context(
+            "Failed to spawn a thread to check for unexpected files in the solutions directory",
+        )?;
 
-    Ok(())
+    if n_solutions > 0
+        && !fmt_cmd
+            .status()
+            .context("Failed to run `rustfmt` on all solution files")?
+            .success()
+    {
+        bail!("Some solutions aren't formatted. Run `rustfmt` on them");
+    }
+
+    handle.join().unwrap()
 }
 
 pub fn check(require_solutions: bool) -> Result<()> {
     let info_file = InfoFile::parse()?;
 
-    // A hack to make `cargo run -- dev check` work when developing Rustlings.
+    if info_file.exercises.len() > MAX_N_EXERCISES {
-    if DEBUG_PROFILE {
+        bail!("The maximum number of exercises is {MAX_N_EXERCISES}");
-        check_cargo_toml(
-            &info_file.exercises,
-            include_str!("../../dev-Cargo.toml"),
-            b"../",
-        )?;
-    } else {
-        let current_cargo_toml =
-            fs::read_to_string("Cargo.toml").context("Failed to read the file `Cargo.toml`")?;
-        check_cargo_toml(&info_file.exercises, &current_cargo_toml, b"")?;
     }
 
-    let target_dir = parse_target_dir()?;
+    if cfg!(debug_assertions) {
-    check_exercises(&info_file, &target_dir)?;
+        // A hack to make `cargo dev check` work when developing Rustlings.
-    check_solutions(require_solutions, &info_file, &target_dir)?;
+        check_cargo_toml(&info_file.exercises, "dev/Cargo.toml", b"../")?;
+    } else {
+        check_cargo_toml(&info_file.exercises, "Cargo.toml", b"")?;
+    }
 
-    println!("\nEverything looks fine!");
+    // Leaking is fine since they are used until the end of the program.
+    let cmd_runner = Box::leak(Box::new(CmdRunner::build()?));
+    let info_file = Box::leak(Box::new(info_file));
+
+    check_exercises(info_file, cmd_runner)?;
+    check_solutions(require_solutions, info_file, cmd_runner)?;
+
+    println!("Everything looks fine!");
 
     Ok(())
 }
 
-const SEPARATOR: &[u8] =
+const SKIP_CHECK_UNSOLVED_HINT: &str = "If this is an introduction exercise that is intended to be already solved, add `skip_check_unsolved = true` to the exercise's metadata in the `info.toml` file";
-    b"\n========================================================================================\n";
-
-const CHECK_EXERCISES_UNSOLVED_ERR: &str = "At least one exercise is already solved or failed to run. See the output above.
-If this is an intro exercise that is intended to be already solved, add `skip_check_unsolved = true` to the exercise's metadata in the `info.toml` file.";

src/dev/new.rs

@@ -1,4 +1,4 @@
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result, bail};
 use std::{
     env::set_current_dir,
     fs::{self, create_dir},
@@ -6,7 +6,7 @@ use std::{
     process::Command,
 };
 
-use crate::CURRENT_FORMAT_VERSION;
+use crate::{CURRENT_FORMAT_VERSION, init::RUST_ANALYZER_TOML};
 
 // Create a directory relative to the current directory and print its path.
 fn create_rel_dir(dir_name: &str, current_dir: &str) -> Result<()> {
@@ -55,13 +55,17 @@ pub fn new(path: &Path, no_git: bool) -> Result<()> {
     write_rel_file(
         "info.toml",
         &dir_path_str,
-        format!("{INFO_FILE_BEFORE_FORMAT_VERSION}{CURRENT_FORMAT_VERSION}{INFO_FILE_AFTER_FORMAT_VERSION}"),
+        format!(
+            "{INFO_FILE_BEFORE_FORMAT_VERSION}{CURRENT_FORMAT_VERSION}{INFO_FILE_AFTER_FORMAT_VERSION}"
+        ),
     )?;
 
     write_rel_file("Cargo.toml", &dir_path_str, CARGO_TOML)?;
 
     write_rel_file("README.md", &dir_path_str, README)?;
 
+    write_rel_file("rust-analyzer.toml", &dir_path_str, RUST_ANALYZER_TOML)?;
+
     create_rel_dir(".vscode", &dir_path_str)?;
     write_rel_file(
         ".vscode/extensions.json",
@@ -74,18 +78,17 @@ pub fn new(path: &Path, no_git: bool) -> Result<()> {
     Ok(())
 }
 
-pub const GITIGNORE: &[u8] = b".rustlings-state.txt
+pub const GITIGNORE: &[u8] = b"Cargo.lock
-Cargo.lock
+target/
-target
+.vscode/
-.vscode
 !.vscode/extensions.json
 ";
 
 const INFO_FILE_BEFORE_FORMAT_VERSION: &str =
-    "# The format version is an indicator of the compatibility of third-party exercises with the
+    "# The format version is an indicator of the compatibility of community exercises with the
 # Rustlings program.
 # The format version is not the same as the version of the Rustlings program.
-# In case Rustlings makes an unavoidable breaking change to the expected format of third-party
+# In case Rustlings makes an unavoidable breaking change to the expected format of community
 # exercises, you would need to raise this version and adapt to the new format.
 # Otherwise, the newest version of the Rustlings program won't be able to run these exercises.
 format_version = ";
@@ -93,7 +96,7 @@ format_version = ";
 const INFO_FILE_AFTER_FORMAT_VERSION: &str = r#"
 
 # Optional multi-line message to be shown to users when just starting with the exercises.
-welcome_message = """Welcome to these third-party Rustlings exercises."""
+welcome_message = """Welcome to these community Rustlings exercises."""
 
 # Optional multi-line message to be shown to users after finishing all exercises.
 final_message = """We hope that you found the exercises helpful :D"""
@@ -128,7 +131,7 @@ bin = []
 
 [package]
 name = "exercises"
-edition = "2021"
+edition = "2024"
 # Don't publish the exercises on crates.io!
 publish = false
 
@@ -137,7 +140,7 @@ publish = false
 
 const README: &str = "# Rustlings 🦀
 
-Welcome to these third-party Rustlings exercises 😃
+Welcome to these community Rustlings exercises 😃
 
 First, [install Rustlings using the official instructions](https://github.com/rust-lang/rustlings) ✅
 

src/dev/update.rs

@@ -4,18 +4,19 @@ use std::fs;
 use crate::{
     cargo_toml::updated_cargo_toml,
     info_file::{ExerciseInfo, InfoFile},
-    DEBUG_PROFILE,
 };
 
 // Update the `Cargo.toml` file.
 fn update_cargo_toml(
     exercise_infos: &[ExerciseInfo],
-    current_cargo_toml: &str,
-    exercise_path_prefix: &[u8],
     cargo_toml_path: &str,
+    exercise_path_prefix: &[u8],
 ) -> Result<()> {
+    let current_cargo_toml = fs::read_to_string(cargo_toml_path)
+        .with_context(|| format!("Failed to read the file `{cargo_toml_path}`"))?;
+
     let updated_cargo_toml =
-        updated_cargo_toml(exercise_infos, current_cargo_toml, exercise_path_prefix)?;
+        updated_cargo_toml(exercise_infos, &current_cargo_toml, exercise_path_prefix)?;
 
     fs::write(cargo_toml_path, updated_cargo_toml)
         .context("Failed to write the `Cargo.toml` file")?;
@@ -26,21 +27,14 @@ fn update_cargo_toml(
 pub fn update() -> Result<()> {
     let info_file = InfoFile::parse()?;
 
-    // A hack to make `cargo run -- dev update` work when developing Rustlings.
+    if cfg!(debug_assertions) {
-    if DEBUG_PROFILE {
+        // A hack to make `cargo dev update` work when developing Rustlings.
-        update_cargo_toml(
+        update_cargo_toml(&info_file.exercises, "dev/Cargo.toml", b"../")
-            &info_file.exercises,
+            .context("Failed to update the file `dev/Cargo.toml`")?;
-            include_str!("../../dev-Cargo.toml"),
-            b"../",
-            "dev/Cargo.toml",
-        )
-        .context("Failed to update the file `dev/Cargo.toml`")?;
 
         println!("Updated `dev/Cargo.toml`");
     } else {
-        let current_cargo_toml =
+        update_cargo_toml(&info_file.exercises, "Cargo.toml", &[])
-            fs::read_to_string("Cargo.toml").context("Failed to read the file `Cargo.toml`")?;
-        update_cargo_toml(&info_file.exercises, &current_cargo_toml, b"", "Cargo.toml")
             .context("Failed to update the file `Cargo.toml`")?;
 
         println!("Updated `Cargo.toml`");

src/embedded.rs

@@ -1,7 +1,7 @@
 use anyhow::{Context, Error, Result};
 use std::{
-    fs::{create_dir, OpenOptions},
+    fs::{self, create_dir},
-    io::{self, Write},
+    io,
 };
 
 use crate::info_file::ExerciseInfo;
@@ -9,29 +9,6 @@ use crate::info_file::ExerciseInfo;
 /// Contains all embedded files.
 pub static EMBEDDED_FILES: EmbeddedFiles = rustlings_macros::include_files!();
 
-#[derive(Clone, Copy)]
-pub enum WriteStrategy {
-    IfNotExists,
-    Overwrite,
-}
-
-impl WriteStrategy {
-    fn write(self, path: &str, content: &[u8]) -> Result<()> {
-        let file = match self {
-            Self::IfNotExists => OpenOptions::new().create_new(true).write(true).open(path),
-            Self::Overwrite => OpenOptions::new()
-                .create(true)
-                .write(true)
-                .truncate(true)
-                .open(path),
-        };
-
-        file.with_context(|| format!("Failed to open the file `{path}` in write mode"))?
-            .write_all(content)
-            .with_context(|| format!("Failed to write the file {path}"))
-    }
-}
-
 // Files related to one exercise.
 struct ExerciseFiles {
     // The content of the exercise file.
@@ -42,6 +19,16 @@ struct ExerciseFiles {
     dir_ind: usize,
 }
 
+fn create_dir_if_not_exists(path: &str) -> Result<()> {
+    if let Err(e) = create_dir(path)
+        && e.kind() != io::ErrorKind::AlreadyExists
+    {
+        return Err(Error::from(e).context(format!("Failed to create the directory {path}")));
+    }
+
+    Ok(())
+}
+
 // A directory in the `exercises/` directory.
 pub struct ExerciseDir {
     pub name: &'static str,
@@ -55,21 +42,13 @@ impl ExerciseDir {
         let mut dir_path = String::with_capacity(20 + self.name.len());
         dir_path.push_str("exercises/");
         dir_path.push_str(self.name);
-
+        create_dir_if_not_exists(&dir_path)?;
-        if let Err(e) = create_dir(&dir_path) {
-            if e.kind() == io::ErrorKind::AlreadyExists {
-                return Ok(());
-            }
-
-            return Err(
-                Error::from(e).context(format!("Failed to create the directory {dir_path}"))
-            );
-        }
 
         let mut readme_path = dir_path;
         readme_path.push_str("/README.md");
 
-        WriteStrategy::Overwrite.write(&readme_path, self.readme)
+        fs::write(&readme_path, self.readme)
+            .with_context(|| format!("Failed to write the file {readme_path}"))
     }
 }
 
@@ -86,17 +65,31 @@ impl EmbeddedFiles {
     pub fn init_exercises_dir(&self, exercise_infos: &[ExerciseInfo]) -> Result<()> {
         create_dir("exercises").context("Failed to create the directory `exercises`")?;
 
-        WriteStrategy::IfNotExists.write(
+        fs::write(
             "exercises/README.md",
             include_bytes!("../exercises/README.md"),
-        )?;
+        )
+        .context("Failed to write the file exercises/README.md")?;
 
         for dir in self.exercise_dirs {
             dir.init_on_disk()?;
         }
 
+        let mut exercise_path = String::with_capacity(64);
+        let prefix = "exercises/";
+        exercise_path.push_str(prefix);
+
         for (exercise_info, exercise_files) in exercise_infos.iter().zip(self.exercise_files) {
-            WriteStrategy::IfNotExists.write(&exercise_info.path(), exercise_files.exercise)?;
+            let dir = &self.exercise_dirs[exercise_files.dir_ind];
+
+            exercise_path.truncate(prefix.len());
+            exercise_path.push_str(dir.name);
+            exercise_path.push('/');
+            exercise_path.push_str(&exercise_info.name);
+            exercise_path.push_str(".rs");
+
+            fs::write(&exercise_path, exercise_files.exercise)
+                .with_context(|| format!("Failed to write the exercise file {exercise_path}"))?;
         }
 
         Ok(())
@@ -107,7 +100,8 @@ impl EmbeddedFiles {
         let dir = &self.exercise_dirs[exercise_files.dir_ind];
 
         dir.init_on_disk()?;
-        WriteStrategy::Overwrite.write(path, exercise_files.exercise)
+        fs::write(path, exercise_files.exercise)
+            .with_context(|| format!("Failed to write the exercise file {path}"))
     }
 
     /// Write the solution file to disk and return its path.
@@ -116,19 +110,25 @@ impl EmbeddedFiles {
         exercise_ind: usize,
         exercise_name: &str,
     ) -> Result<String> {
+        create_dir_if_not_exists("solutions")?;
+
         let exercise_files = &self.exercise_files[exercise_ind];
         let dir = &self.exercise_dirs[exercise_files.dir_ind];
 
         // 14 = 10 + 1 + 3
         // solutions/ + / + .rs
-        let mut solution_path = String::with_capacity(14 + dir.name.len() + exercise_name.len());
+        let mut dir_path = String::with_capacity(14 + dir.name.len() + exercise_name.len());
-        solution_path.push_str("solutions/");
+        dir_path.push_str("solutions/");
-        solution_path.push_str(dir.name);
+        dir_path.push_str(dir.name);
+        create_dir_if_not_exists(&dir_path)?;
+
+        let mut solution_path = dir_path;
         solution_path.push('/');
         solution_path.push_str(exercise_name);
         solution_path.push_str(".rs");
 
-        WriteStrategy::Overwrite.write(&solution_path, exercise_files.solution)?;
+        fs::write(&solution_path, exercise_files.solution)
+            .with_context(|| format!("Failed to write the solution file {solution_path}"))?;
 
         Ok(solution_path)
     }
@@ -152,7 +152,7 @@ mod tests {
 
     #[test]
     fn dirs() {
-        let exercises = toml_edit::de::from_str::<InfoFile>(EMBEDDED_FILES.info_file)
+        let exercises = toml::de::from_str::<InfoFile>(EMBEDDED_FILES.info_file)
             .expect("Failed to parse `info.toml`")
             .exercises;
 

src/exercise.rs

@@ -1,46 +1,64 @@
 use anyhow::Result;
-use crossterm::style::{style, StyledContent, Stylize};
+use crossterm::{
-use std::{
+    QueueableCommand,
-    fmt::{self, Display, Formatter},
+    style::{Attribute, Color, ResetColor, SetAttribute, SetForegroundColor},
-    io::Write,
-    path::{Path, PathBuf},
-    process::Command,
 };
+use std::io::{self, StdoutLock, Write};
 
 use crate::{
-    cmd::{run_cmd, CargoCmd},
+    cmd::CmdRunner,
-    in_official_repo,
+    term::{self, CountedWrite, file_path, terminal_file_link, write_ansi},
-    terminal_link::TerminalFileLink,
-    DEBUG_PROFILE,
 };
 
 /// The initial capacity of the output buffer.
 pub const OUTPUT_CAPACITY: usize = 1 << 14;
 
+pub fn solution_link_line(
+    stdout: &mut StdoutLock,
+    solution_path: &str,
+    emit_file_links: bool,
+) -> io::Result<()> {
+    stdout.queue(SetAttribute(Attribute::Bold))?;
+    stdout.write_all(b"Solution")?;
+    stdout.queue(ResetColor)?;
+    stdout.write_all(b" for comparison: ")?;
+    file_path(stdout, Color::Cyan, |writer| {
+        if emit_file_links && let Some(canonical_path) = term::canonicalize(solution_path) {
+            terminal_file_link(writer, solution_path, &canonical_path)
+        } else {
+            writer.stdout().write_all(solution_path.as_bytes())
+        }
+    })?;
+    stdout.write_all(b"\n")
+}
+
 // Run an exercise binary and append its output to the `output` buffer.
 // Compilation must be done before calling this method.
-fn run_bin(bin_name: &str, output: &mut Vec<u8>, target_dir: &Path) -> Result<bool> {
+fn run_bin(
-    writeln!(output, "{}", "Output".underlined())?;
+    bin_name: &str,
+    mut output: Option<&mut Vec<u8>>,
+    cmd_runner: &CmdRunner,
+) -> Result<bool> {
+    if let Some(output) = output.as_deref_mut() {
+        write_ansi(output, SetAttribute(Attribute::Underlined));
+        output.extend_from_slice(b"Output");
+        write_ansi(output, ResetColor);
+        output.push(b'\n');
+    }
 
-    // 7 = "/debug/".len()
+    let success = cmd_runner.run_debug_bin(bin_name, output.as_deref_mut())?;
-    let mut bin_path = PathBuf::with_capacity(target_dir.as_os_str().len() + 7 + bin_name.len());
-    bin_path.push(target_dir);
-    bin_path.push("debug");
-    bin_path.push(bin_name);
 
-    let success = run_cmd(Command::new(&bin_path), &bin_path.to_string_lossy(), output)?;
+    if let Some(output) = output
-
+        && !success
-    if !success {
+    {
         // This output is important to show the user that something went wrong.
         // Otherwise, calling something like `exit(1)` in an exercise without further output
         // leaves the user confused about why the exercise isn't done yet.
-        writeln!(
+        write_ansi(output, SetAttribute(Attribute::Bold));
-            output,
+        write_ansi(output, SetForegroundColor(Color::Red));
-            "{}",
+        output.extend_from_slice(b"The exercise didn't run successfully (nonzero exit code)");
-            "The exercise didn't run successfully (nonzero exit code)"
+        write_ansi(output, ResetColor);
-                .bold()
+        output.push(b'\n');
-                .red(),
-        )?;
     }
 
     Ok(success)
@@ -52,114 +70,133 @@ pub struct Exercise {
     pub name: &'static str,
     /// Path of the exercise file starting with the `exercises/` directory.
     pub path: &'static str,
+    pub canonical_path: Option<String>,
     pub test: bool,
     pub strict_clippy: bool,
-    pub hint: String,
+    pub hint: &'static str,
     pub done: bool,
 }
 
 impl Exercise {
-    pub fn terminal_link(&self) -> StyledContent<TerminalFileLink<'_>> {
+    pub fn terminal_file_link<'a>(
-        style(TerminalFileLink(self.path)).underlined().blue()
+        &self,
-    }
+        writer: &mut impl CountedWrite<'a>,
-}
+        emit_file_links: bool,
-
+    ) -> io::Result<()> {
-impl Display for Exercise {
+        file_path(writer, Color::Blue, |writer| {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+            if emit_file_links && let Some(canonical_path) = self.canonical_path.as_deref() {
-        self.path.fmt(f)
+                terminal_file_link(writer, self.path, canonical_path)
+            } else {
+                writer.write_str(self.path)
+            }
+        })
     }
 }
 
 pub trait RunnableExercise {
     fn name(&self) -> &str;
+    fn dir(&self) -> Option<&str>;
     fn strict_clippy(&self) -> bool;
     fn test(&self) -> bool;
 
     // Compile, check and run the exercise or its solution (depending on `bin_name´).
     // The output is written to the `output` buffer after clearing it.
-    fn run(&self, bin_name: &str, output: &mut Vec<u8>, target_dir: &Path) -> Result<bool> {
+    fn run<const FORCE_STRICT_CLIPPY: bool>(
-        output.clear();
+        &self,
-
+        bin_name: &str,
-        // Developing the official Rustlings.
+        mut output: Option<&mut Vec<u8>>,
-        let dev = DEBUG_PROFILE && in_official_repo();
+        cmd_runner: &CmdRunner,
-
+    ) -> Result<bool> {
-        let build_success = CargoCmd {
+        if let Some(output) = output.as_deref_mut() {
-            subcommand: "build",
+            output.clear();
-            args: &[],
-            bin_name,
-            description: "cargo build …",
-            hide_warnings: false,
-            target_dir,
-            output,
-            dev,
         }
-        .run()?;
+
+        let build_success = cmd_runner
+            .cargo("build", bin_name, output.as_deref_mut())
+            .run("cargo build …")?;
         if !build_success {
             return Ok(false);
         }
 
-        // Discard the output of `cargo build` because it will be shown again by Clippy.
+        // Discard the compiler output because it will be shown again by `cargo test` or Clippy.
-        output.clear();
+        if let Some(output) = output.as_deref_mut() {
+            output.clear();
+        }
 
-        // `--profile test` is required to also check code with `[cfg(test)]`.
+        if self.test() {
-        let clippy_args: &[&str] = if self.strict_clippy() {
+            let output_is_some = output.is_some();
-            &["--profile", "test", "--", "-D", "warnings"]
+            let mut test_cmd = cmd_runner.cargo("test", bin_name, output.as_deref_mut());
+            if output_is_some {
+                test_cmd.args(["--", "--color", "always", "--format", "pretty"]);
+            }
+            let test_success = test_cmd.run("cargo test …")?;
+            if !test_success {
+                run_bin(bin_name, output, cmd_runner)?;
+                return Ok(false);
+            }
+
+            // Discard the compiler output because it will be shown again by Clippy.
+            if let Some(output) = output.as_deref_mut() {
+                output.clear();
+            }
+        }
+
+        let mut clippy_cmd = cmd_runner.cargo("clippy", bin_name, output.as_deref_mut());
+
+        // `--profile test` is required to also check code with `#[cfg(test)]`.
+        if FORCE_STRICT_CLIPPY || self.strict_clippy() {
+            clippy_cmd.args(["--profile", "test", "--", "-D", "warnings"]);
         } else {
-            &["--profile", "test"]
+            clippy_cmd.args(["--profile", "test"]);
-        };
-        let clippy_success = CargoCmd {
-            subcommand: "clippy",
-            args: clippy_args,
-            bin_name,
-            description: "cargo clippy …",
-            hide_warnings: false,
-            target_dir,
-            output,
-            dev,
-        }
-        .run()?;
-        if !clippy_success {
-            return Ok(false);
         }
 
-        if !self.test() {
+        let clippy_success = clippy_cmd.run("cargo clippy …")?;
-            return run_bin(bin_name, output, target_dir);
+        let run_success = run_bin(bin_name, output, cmd_runner)?;
-        }
 
-        let test_success = CargoCmd {
+        Ok(clippy_success && run_success)
-            subcommand: "test",
-            args: &["--", "--color", "always", "--show-output"],
-            bin_name,
-            description: "cargo test …",
-            // Hide warnings because they are shown by Clippy.
-            hide_warnings: true,
-            target_dir,
-            output,
-            dev,
-        }
-        .run()?;
-
-        let run_success = run_bin(bin_name, output, target_dir)?;
-
-        Ok(test_success && run_success)
     }
 
     /// Compile, check and run the exercise.
     /// The output is written to the `output` buffer after clearing it.
     #[inline]
-    fn run_exercise(&self, output: &mut Vec<u8>, target_dir: &Path) -> Result<bool> {
+    fn run_exercise(&self, output: Option<&mut Vec<u8>>, cmd_runner: &CmdRunner) -> Result<bool> {
-        self.run(self.name(), output, target_dir)
+        self.run::<false>(self.name(), output, cmd_runner)
     }
 
     /// Compile, check and run the exercise's solution.
     /// The output is written to the `output` buffer after clearing it.
-    fn run_solution(&self, output: &mut Vec<u8>, target_dir: &Path) -> Result<bool> {
+    fn run_solution(&self, output: Option<&mut Vec<u8>>, cmd_runner: &CmdRunner) -> Result<bool> {
         let name = self.name();
-        let mut bin_name = String::with_capacity(name.len());
+        let mut bin_name = String::with_capacity(name.len() + 4);
         bin_name.push_str(name);
         bin_name.push_str("_sol");
 
-        self.run(&bin_name, output, target_dir)
+        self.run::<true>(&bin_name, output, cmd_runner)
+    }
+
+    fn sol_path(&self) -> String {
+        let name = self.name();
+
+        let mut path = if let Some(dir) = self.dir() {
+            // 14 = 10 + 1 + 3
+            // solutions/ + / + .rs
+            let mut path = String::with_capacity(14 + dir.len() + name.len());
+            path.push_str("solutions/");
+            path.push_str(dir);
+            path.push('/');
+            path
+        } else {
+            // 13 = 10 + 3
+            // solutions/ + .rs
+            let mut path = String::with_capacity(13 + name.len());
+            path.push_str("solutions/");
+            path
+        };
+
+        path.push_str(name);
+        path.push_str(".rs");
+
+        path
     }
 }
 
@@ -169,6 +206,11 @@ impl RunnableExercise for Exercise {
         self.name
     }
 
+    #[inline]
+    fn dir(&self) -> Option<&str> {
+        self.dir
+    }
+
     #[inline]
     fn strict_clippy(&self) -> bool {
         self.strict_clippy

src/info_file.rs

@@ -1,4 +1,4 @@
-use anyhow::{bail, Context, Error, Result};
+use anyhow::{Context, Error, Result, bail};
 use serde::Deserialize;
 use std::{fs, io::ErrorKind};
 
@@ -52,30 +52,6 @@ impl ExerciseInfo {
 
         path
     }
-
-    /// Path to the solution file starting with the `solutions/` directory.
-    pub fn sol_path(&self) -> String {
-        let mut path = if let Some(dir) = &self.dir {
-            // 14 = 10 + 1 + 3
-            // solutions/ + / + .rs
-            let mut path = String::with_capacity(14 + dir.len() + self.name.len());
-            path.push_str("solutions/");
-            path.push_str(dir);
-            path.push('/');
-            path
-        } else {
-            // 13 = 10 + 3
-            // solutions/ + .rs
-            let mut path = String::with_capacity(13 + self.name.len());
-            path.push_str("solutions/");
-            path
-        };
-
-        path.push_str(&self.name);
-        path.push_str(".rs");
-
-        path
-    }
 }
 
 impl RunnableExercise for ExerciseInfo {
@@ -84,6 +60,11 @@ impl RunnableExercise for ExerciseInfo {
         &self.name
     }
 
+    #[inline]
+    fn dir(&self) -> Option<&str> {
+        self.dir.as_deref()
+    }
+
     #[inline]
     fn strict_clippy(&self) -> bool {
         self.strict_clippy
@@ -98,7 +79,7 @@ impl RunnableExercise for ExerciseInfo {
 /// The deserialized `info.toml` file.
 #[derive(Deserialize)]
 pub struct InfoFile {
-    /// For possible breaking changes in the future for third-party exercises.
+    /// For possible breaking changes in the future for community exercises.
     pub format_version: u8,
     /// Shown to users when starting with the exercises.
     pub welcome_message: Option<String>,
@@ -110,15 +91,15 @@ pub struct InfoFile {
 
 impl InfoFile {
     /// Official exercises: Parse the embedded `info.toml` file.
-    /// Third-party exercises: Parse the `info.toml` file in the current directory.
+    /// Community exercises: Parse the `info.toml` file in the current directory.
     pub fn parse() -> Result<Self> {
         // Read a local `info.toml` if it exists.
         let slf = match fs::read_to_string("info.toml") {
-            Ok(file_content) => toml_edit::de::from_str::<Self>(&file_content)
+            Ok(file_content) => toml::de::from_str::<Self>(&file_content)
                 .context("Failed to parse the `info.toml` file")?,
             Err(e) => {
                 if e.kind() == ErrorKind::NotFound {
-                    return toml_edit::de::from_str(EMBEDDED_FILES.info_file)
+                    return toml::de::from_str(EMBEDDED_FILES.info_file)
                         .context("Failed to parse the embedded `info.toml` file");
                 }
 
@@ -135,4 +116,4 @@ impl InfoFile {
 }
 
 const NO_EXERCISES_ERR: &str = "There are no exercises yet!
-If you are developing third-party exercises, add at least one exercise before testing.";
+Add at least one exercise before testing.";

src/init.rs

@@ -1,32 +1,122 @@
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result, bail};
-use crossterm::style::Stylize;
+use crossterm::{
+    QueueableCommand,
+    style::{Attribute, Color, ResetColor, SetAttribute, SetForegroundColor},
+};
+use serde::Deserialize;
 use std::{
     env::set_current_dir,
     fs::{self, create_dir},
-    io::ErrorKind,
+    io::{self, Write},
-    path::Path,
+    path::{Path, PathBuf},
     process::{Command, Stdio},
 };
 
-use crate::{cargo_toml::updated_cargo_toml, embedded::EMBEDDED_FILES, info_file::InfoFile};
+use crate::{
+    cargo_toml::updated_cargo_toml, embedded::EMBEDDED_FILES, exercise::RunnableExercise,
+    info_file::InfoFile, term::press_enter_prompt,
+};
+
+#[derive(Deserialize)]
+struct CargoLocateProject {
+    root: PathBuf,
+}
 
 pub fn init() -> Result<()> {
-    // Prevent initialization in a directory that contains the file `Cargo.toml`.
+    let rustlings_dir = Path::new("rustlings");
-    // This can mean that Rustlings was already initialized in this directory.
+    if rustlings_dir.exists() {
-    // Otherwise, this can cause problems with Cargo workspaces.
+        bail!(RUSTLINGS_DIR_ALREADY_EXISTS_ERR);
-    if Path::new("Cargo.toml").exists() {
-        bail!(CARGO_TOML_EXISTS_ERR);
     }
 
-    let rustlings_path = Path::new("rustlings");
+    let locate_project_output = Command::new("cargo")
-    if let Err(e) = create_dir(rustlings_path) {
+        .arg("locate-project")
-        if e.kind() == ErrorKind::AlreadyExists {
+        .arg("-q")
-            bail!(RUSTLINGS_DIR_ALREADY_EXISTS_ERR);
+        .arg("--workspace")
+        .stdin(Stdio::null())
+        .stderr(Stdio::null())
+        .output()
+        .context(
+            "Failed to run the command `cargo locate-project …`\n\
+             Did you already install Rust?\n\
+             Try running `cargo --version` to diagnose the problem.",
+        )?;
+
+    if !Command::new("cargo")
+        .arg("clippy")
+        .arg("--version")
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .status()
+        .context("Failed to run the command `cargo clippy --version`")?
+        .success()
+    {
+        bail!(
+            "Clippy, the official Rust linter, is missing.\n\
+             Please install it first before initializing Rustlings."
+        )
+    }
+
+    let mut stdout = io::stdout().lock();
+    let mut init_git = true;
+
+    if locate_project_output.status.success() {
+        if Path::new("exercises").exists() && Path::new("solutions").exists() {
+            bail!(IN_INITIALIZED_DIR_ERR);
         }
-        return Err(e.into());
+
+        let workspace_manifest =
+            serde_json::de::from_slice::<CargoLocateProject>(&locate_project_output.stdout)
+                .context(
+                    "Failed to read the field `root` from the output of `cargo locate-project …`",
+                )?
+                .root;
+
+        let workspace_manifest_content = fs::read_to_string(&workspace_manifest)
+            .with_context(|| format!("Failed to read the file {}", workspace_manifest.display()))?;
+        if !workspace_manifest_content.contains("[workspace]")
+            && !workspace_manifest_content.contains("workspace.")
+        {
+            bail!(
+                "The current directory is already part of a Cargo project.\n\
+                 Please initialize Rustlings in a different directory"
+            );
+        }
+
+        stdout.write_all(b"This command will create the directory `rustlings/` as a member of this Cargo workspace.\n\
+                           Press ENTER to continue ")?;
+        press_enter_prompt(&mut stdout)?;
+
+        // Make sure "rustlings" is added to `workspace.members` by making
+        // Cargo initialize a new project.
+        let status = Command::new("cargo")
+            .arg("new")
+            .arg("-q")
+            .arg("--vcs")
+            .arg("none")
+            .arg("rustlings")
+            .stdin(Stdio::null())
+            .stdout(Stdio::null())
+            .status()?;
+        if !status.success() {
+            bail!(
+                "Failed to initialize a new Cargo workspace member.\n\
+                 Please initialize Rustlings in a different directory"
+            );
+        }
+
+        stdout.write_all(b"The directory `rustlings` has been added to `workspace.members` in the `Cargo.toml` file of this Cargo workspace.\n")?;
+        fs::remove_dir_all("rustlings")
+            .context("Failed to remove the temporary directory `rustlings/`")?;
+        init_git = false;
+    } else {
+        stdout.write_all(b"This command will create the directory `rustlings/` which will contain the exercises.\n\
+                           Press ENTER to continue ")?;
+        press_enter_prompt(&mut stdout)?;
     }
 
-    set_current_dir("rustlings")
+    create_dir(rustlings_dir).context("Failed to create the `rustlings/` directory")?;
+    set_current_dir(rustlings_dir)
         .context("Failed to change the current directory to `rustlings/`")?;
 
     let info_file = InfoFile::parse()?;
@@ -35,6 +125,11 @@ pub fn init() -> Result<()> {
         .context("Failed to initialize the `rustlings/exercises` directory")?;
 
     create_dir("solutions").context("Failed to create the `solutions/` directory")?;
+    fs::write(
+        "solutions/README.md",
+        include_bytes!("../solutions/README.md"),
+    )
+    .context("Failed to create the file rustlings/solutions/README.md")?;
     for dir in EMBEDDED_FILES.exercise_dirs {
         let mut dir_path = String::with_capacity(10 + dir.name.len());
         dir_path.push_str("solutions/");
@@ -63,6 +158,9 @@ pub fn init() -> Result<()> {
     fs::write("Cargo.toml", updated_cargo_toml)
         .context("Failed to create the file `rustlings/Cargo.toml`")?;
 
+    fs::write("rust-analyzer.toml", RUST_ANALYZER_TOML)
+        .context("Failed to create the file `rustlings/rust-analyzer.toml`")?;
+
     fs::write(".gitignore", GITIGNORE)
         .context("Failed to create the file `rustlings/.gitignore`")?;
 
@@ -70,18 +168,24 @@ pub fn init() -> Result<()> {
     fs::write(".vscode/extensions.json", VS_CODE_EXTENSIONS_JSON)
         .context("Failed to create the file `rustlings/.vscode/extensions.json`")?;
 
-    // Ignore any Git error because Git initialization is not required.
+    if init_git {
-    let _ = Command::new("git")
+        // Ignore any Git error because Git initialization is not required.
-        .arg("init")
+        let _ = Command::new("git")
-        .stdin(Stdio::null())
+            .arg("init")
-        .stderr(Stdio::null())
+            .stdin(Stdio::null())
-        .status();
+            .stdout(Stdio::null())
+            .stderr(Stdio::null())
+            .status();
+    }
 
-    println!(
+    stdout.queue(SetForegroundColor(Color::Green))?;
-        "\n{}\n\n{}",
+    stdout.write_all("Initialization done ✓".as_bytes())?;
-        "Initialization done ✓".green(),
+    stdout.queue(ResetColor)?;
-        POST_INIT_MSG.bold(),
+    stdout.write_all(b"\n\n")?;
-    );
+
+    stdout.queue(SetAttribute(Attribute::Bold))?;
+    stdout.write_all(POST_INIT_MSG)?;
+    stdout.queue(ResetColor)?;
 
     Ok(())
 }
@@ -92,19 +196,22 @@ const INIT_SOLUTION_FILE: &[u8] = b"fn main() {
 }
 ";
 
-const GITIGNORE: &[u8] = b".rustlings-state.txt
+pub const RUST_ANALYZER_TOML: &[u8] = br#"check.command = "clippy"
-solutions
+check.extraArgs = ["--profile", "test"]
-Cargo.lock
+cargo.targetDir = true
-target
+"#;
-.vscode
+
+const GITIGNORE: &[u8] = b"Cargo.lock
+target/
+.vscode/
 ";
 
 pub const VS_CODE_EXTENSIONS_JSON: &[u8] = br#"{"recommendations":["rust-lang.rust-analyzer"]}"#;
 
-const CARGO_TOML_EXISTS_ERR: &str = "The current directory contains the file `Cargo.toml`.
+const IN_INITIALIZED_DIR_ERR: &str = "It looks like Rustlings is already initialized in this directory.
 
 If you already initialized Rustlings, run the command `rustlings` for instructions on getting started with the exercises.
-Otherwise, please run `rustlings init` again in another directory.";
+Otherwise, please run `rustlings init` again in a different directory.";
 
 const RUSTLINGS_DIR_ALREADY_EXISTS_ERR: &str =
     "A directory with the name `rustlings` already exists in the current directory.
@@ -112,5 +219,6 @@ You probably already initialized Rustlings.
 Run `cd rustlings`
 Then run `rustlings` again";
 
-const POST_INIT_MSG: &str = "Run `cd rustlings` to go into the generated directory.
+const POST_INIT_MSG: &[u8] = b"Run `cd rustlings` to go into the generated directory.
-Then run `rustlings` to get started.";
+Then run `rustlings` to get started.
+";

src/list.rs

@@ -1,90 +1,134 @@
-use anyhow::Result;
+use anyhow::{Context, Result};
 use crossterm::{
-    event::{self, Event, KeyCode, KeyEventKind},
+    QueueableCommand, cursor,
-    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
+    event::{
-    ExecutableCommand,
+        self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode, KeyEventKind, MouseEventKind,
+    },
+    terminal::{
+        DisableLineWrap, EnableLineWrap, EnterAlternateScreen, LeaveAlternateScreen,
+        disable_raw_mode, enable_raw_mode,
+    },
 };
-use ratatui::{backend::CrosstermBackend, Terminal};
+use std::io::{self, StdoutLock, Write};
-use std::io;
 
 use crate::app_state::AppState;
 
-use self::state::{Filter, UiState};
+use self::state::{Filter, ListState};
 
+mod scroll_state;
 mod state;
 
+fn handle_list(app_state: &mut AppState, stdout: &mut StdoutLock) -> Result<()> {
+    let mut list_state = ListState::build(app_state, stdout)?;
+    let mut is_searching = false;
+
+    loop {
+        match event::read().context("Failed to read terminal event")? {
+            Event::Key(key) => {
+                match key.kind {
+                    KeyEventKind::Release => continue,
+                    KeyEventKind::Press | KeyEventKind::Repeat => (),
+                }
+
+                list_state.message.clear();
+
+                if is_searching {
+                    match key.code {
+                        KeyCode::Esc | KeyCode::Enter => {
+                            is_searching = false;
+                            list_state.search_query.clear();
+                        }
+                        KeyCode::Char(c) => {
+                            list_state.search_query.push(c);
+                            list_state.apply_search_query();
+                        }
+                        KeyCode::Backspace => {
+                            list_state.search_query.pop();
+                            list_state.apply_search_query();
+                        }
+                        _ => continue,
+                    }
+
+                    list_state.draw(stdout)?;
+                    continue;
+                }
+
+                match key.code {
+                    KeyCode::Char('q') => return Ok(()),
+                    KeyCode::Down | KeyCode::Char('j') => list_state.select_next(),
+                    KeyCode::Up | KeyCode::Char('k') => list_state.select_previous(),
+                    KeyCode::Home | KeyCode::Char('g') => list_state.select_first(),
+                    KeyCode::End | KeyCode::Char('G') => list_state.select_last(),
+                    KeyCode::Char('d') => {
+                        if list_state.filter() == Filter::Done {
+                            list_state.set_filter(Filter::None);
+                            list_state.message.push_str("Disabled filter DONE");
+                        } else {
+                            list_state.set_filter(Filter::Done);
+                            list_state.message.push_str(
+                                "Enabled filter DONE │ Press d again to disable the filter",
+                            );
+                        }
+                    }
+                    KeyCode::Char('p') => {
+                        if list_state.filter() == Filter::Pending {
+                            list_state.set_filter(Filter::None);
+                            list_state.message.push_str("Disabled filter PENDING");
+                        } else {
+                            list_state.set_filter(Filter::Pending);
+                            list_state.message.push_str(
+                                "Enabled filter PENDING │ Press p again to disable the filter",
+                            );
+                        }
+                    }
+                    KeyCode::Char('r') => list_state.reset_selected()?,
+                    KeyCode::Char('c') => {
+                        if list_state.selected_to_current_exercise()? {
+                            return Ok(());
+                        }
+                    }
+                    KeyCode::Char('s' | '/') => {
+                        is_searching = true;
+                        list_state.apply_search_query();
+                    }
+                    // Redraw to remove the message.
+                    KeyCode::Esc => (),
+                    _ => continue,
+                }
+            }
+            Event::Mouse(event) => match event.kind {
+                MouseEventKind::ScrollDown => list_state.select_next(),
+                MouseEventKind::ScrollUp => list_state.select_previous(),
+                _ => continue,
+            },
+            Event::Resize(width, height) => list_state.set_term_size(width, height),
+            // Ignore
+            Event::FocusGained | Event::FocusLost => continue,
+        }
+
+        list_state.draw(stdout)?;
+    }
+}
+
 pub fn list(app_state: &mut AppState) -> Result<()> {
     let mut stdout = io::stdout().lock();
-    stdout.execute(EnterAlternateScreen)?;
+    stdout
+        .queue(EnterAlternateScreen)?
+        .queue(cursor::Hide)?
+        .queue(DisableLineWrap)?
+        .queue(EnableMouseCapture)?;
     enable_raw_mode()?;
 
-    let mut terminal = Terminal::new(CrosstermBackend::new(&mut stdout))?;
+    let res = handle_list(app_state, &mut stdout);
-    terminal.clear()?;
 
-    let mut ui_state = UiState::new(app_state);
+    // Restore the terminal even if we got an error.
-
+    stdout
-    'outer: loop {
+        .queue(LeaveAlternateScreen)?
-        terminal.draw(|frame| ui_state.draw(frame).unwrap())?;
+        .queue(cursor::Show)?
-
+        .queue(EnableLineWrap)?
-        let key = loop {
+        .queue(DisableMouseCapture)?
-            match event::read()? {
+        .flush()?;
-                Event::Key(key) => match key.kind {
-                    KeyEventKind::Press | KeyEventKind::Repeat => break key,
-                    KeyEventKind::Release => (),
-                },
-                // Redraw
-                Event::Resize(_, _) => continue 'outer,
-                // Ignore
-                Event::FocusGained | Event::FocusLost | Event::Mouse(_) | Event::Paste(_) => (),
-            }
-        };
-
-        ui_state.message.clear();
-
-        match key.code {
-            KeyCode::Char('q') => break,
-            KeyCode::Down | KeyCode::Char('j') => ui_state.select_next(),
-            KeyCode::Up | KeyCode::Char('k') => ui_state.select_previous(),
-            KeyCode::Home | KeyCode::Char('g') => ui_state.select_first(),
-            KeyCode::End | KeyCode::Char('G') => ui_state.select_last(),
-            KeyCode::Char('d') => {
-                let message = if ui_state.filter == Filter::Done {
-                    ui_state.filter = Filter::None;
-                    "Disabled filter DONE"
-                } else {
-                    ui_state.filter = Filter::Done;
-                    "Enabled filter DONE │ Press d again to disable the filter"
-                };
-
-                ui_state = ui_state.with_updated_rows();
-                ui_state.message.push_str(message);
-            }
-            KeyCode::Char('p') => {
-                let message = if ui_state.filter == Filter::Pending {
-                    ui_state.filter = Filter::None;
-                    "Disabled filter PENDING"
-                } else {
-                    ui_state.filter = Filter::Pending;
-                    "Enabled filter PENDING │ Press p again to disable the filter"
-                };
-
-                ui_state = ui_state.with_updated_rows();
-                ui_state.message.push_str(message);
-            }
-            KeyCode::Char('r') => {
-                ui_state = ui_state.with_reset_selected()?;
-            }
-            KeyCode::Char('c') => {
-                ui_state.selected_to_current_exercise()?;
-                ui_state = ui_state.with_updated_rows();
-            }
-            _ => (),
-        }
-    }
-
-    drop(terminal);
-    stdout.execute(LeaveAlternateScreen)?;
     disable_raw_mode()?;
 
-    Ok(())
+    res
 }