write input files to disk before running exercise

src/app_state.rs

@@ -81,9 +81,11 @@ impl AppState {
             })?;
 
         let dir_canonical_path = term::canonicalize("exercises");
+        let official_exercises = !Path::new("info.toml").exists();
         let mut exercises = exercise_infos
             .into_iter()
-            .map(|exercise_info| {
+            .enumerate()
+            .map(|(i, exercise_info)| {
                 let canonical_path = dir_canonical_path.as_deref().map(|dir_canonical_path| {
                     let mut canonical_path;
                     if let Some(dir) = exercise_info.dir {
@@ -105,10 +107,16 @@ impl AppState {
                     canonical_path.push_str(".rs");
                     canonical_path
                 });
+                let embedded_input_files = if official_exercises {
+                    EMBEDDED_FILES.exercise_files[i].input_files
+                } else {
+                    &[]
+                };
 
                 Exercise {
                     name: exercise_info.name,
                     dir: exercise_info.dir,
+                    embedded_input_files,
                     // LEAKING: For `Editor::open`. The app state is used until the end of the program.
                     path: exercise_info.path().leak(),
                     canonical_path,
@@ -173,7 +181,7 @@ impl AppState {
             final_message,
             state_file,
             file_buf,
-            official_exercises: !Path::new("info.toml").exists(),
+            official_exercises,
             cmd_runner,
             // VS Code has its own file link handling
             emit_file_links: !vs_code_term,
@@ -597,6 +605,7 @@ mod tests {
         Exercise {
             name: "0",
             dir: None,
+            embedded_input_files: &[],
             path: "exercises/0.rs",
             canonical_path: None,
             test: false,

src/embedded.rs

@@ -10,7 +10,7 @@ use crate::info_file::ExerciseInfo;
 pub static EMBEDDED_FILES: EmbeddedFiles = rustlings_macros::include_files!();
 
 // Files related to one exercise.
-struct ExerciseFiles {
+pub struct ExerciseFiles {
     // The content of the exercise file.
     exercise: &'static [u8],
     // The content of the solution file.
@@ -18,7 +18,7 @@ struct ExerciseFiles {
     // Index of the related `ExerciseDir` in `EmbeddedFiles::exercise_dirs`.
     dir_ind: usize,
     // Files that are read by the exercise.
-    input_files: &'static [InputFile],
+    pub input_files: &'static [InputFile],
 }
 
 // Input files that may be read by exercises.
@@ -64,7 +64,7 @@ impl ExerciseDir {
 pub struct EmbeddedFiles {
     /// The content of the `info.toml` file.
     pub info_file: &'static str,
-    exercise_files: &'static [ExerciseFiles],
+    pub exercise_files: &'static [ExerciseFiles],
     pub exercise_dirs: &'static [ExerciseDir],
 }
 

src/exercise.rs

@@ -1,4 +1,4 @@
-use anyhow::Result;
+use anyhow::{Context, Result};
 use crossterm::{
     QueueableCommand,
     style::{Attribute, Color, ResetColor, SetAttribute, SetForegroundColor},
@@ -7,6 +7,7 @@ use std::io::{self, StdoutLock, Write};
 
 use crate::{
     cmd::CmdRunner,
+    embedded::InputFile,
     term::{self, CountedWrite, file_path, terminal_file_link, write_ansi},
 };
 
@@ -69,6 +70,7 @@ fn run_bin(
 pub struct Exercise {
     pub name: &'static str,
     pub dir: Option<&'static str>,
+    pub embedded_input_files: &'static [InputFile],
     /// Path of the exercise file starting with the `exercises/` directory.
     pub path: &'static str,
     pub canonical_path: Option<String>,
@@ -99,6 +101,7 @@ pub trait RunnableExercise {
     fn dir(&self) -> Option<&str>;
     fn strict_clippy(&self) -> bool;
     fn test(&self) -> bool;
+    fn embedded_input_files(&self) -> &[InputFile];
 
     // Compile, check and run the exercise or its solution (depending on `bin_name´).
     // The output is written to the `output` buffer after clearing it.
@@ -112,6 +115,19 @@ pub trait RunnableExercise {
             output.clear();
         }
 
+        // Input files are already written to disk during `rustlings init`.
+        // We repeat it here to ensure an exercise doesn't fail because the
+        // input files were deleted or modified in the meantime. Note that
+        // `self.embedded_input_files()` is empty for community exercises.
+        for input_file in self.embedded_input_files() {
+            let name = input_file.name;
+            let path = match self.dir() {
+                Some(dir) => format!("exercises/{dir}/{name}"),
+                None => format!("exercises/{name}"),
+            };
+            std::fs::write(path, input_file.content).context("failed to write input file")?;
+        }
+
         let build_success = cmd_runner
             .cargo("build", bin_name, output.as_deref_mut())
             .run("cargo build …")?;
@@ -224,4 +240,8 @@ impl RunnableExercise for Exercise {
     fn test(&self) -> bool {
         self.test
     }
+
+    fn embedded_input_files(&self) -> &[InputFile] {
+        self.embedded_input_files
+    }
 }

src/info_file.rs

@@ -2,7 +2,10 @@ use anyhow::{Context, Error, Result, bail};
 use serde::Deserialize;
 use std::{fs, io::ErrorKind};
 
-use crate::{embedded::EMBEDDED_FILES, exercise::RunnableExercise};
+use crate::{
+    embedded::{EMBEDDED_FILES, InputFile},
+    exercise::RunnableExercise,
+};
 
 /// Deserialized from the `info.toml` file.
 #[derive(Deserialize)]
@@ -72,6 +75,11 @@ impl RunnableExercise for ExerciseInfo<'_> {
     fn test(&self) -> bool {
         self.test
     }
+
+    fn embedded_input_files(&self) -> &[InputFile] {
+        // We don't have the input files embedded for communtiy exercises.
+        &[]
+    }
 }
 
 /// The deserialized `info.toml` file.