Run rustfmt on solutions in dev check

.github/workflows/rust.yml

@@ -24,8 +24,6 @@ jobs:
           globs: "exercises/**/*.md"
       - name: Run cargo fmt
         run: cargo fmt --all --check
-      - name: Run rustfmt on solutions
-        run: rustfmt --check --edition 2021 --color always solutions/**/*.rs
   test:
     runs-on: ${{ matrix.os }}
     strategy:

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - Run the final check of all exercises in parallel.
 - Small exercise improvements.
+- `dev check`: Check that all solutions are formatted with `rustfmt`.
 
 <a name="6.1.0"></a>
 

Cargo.toml

@@ -15,7 +15,7 @@ authors = [
 ]
 repository = "https://github.com/rust-lang/rustlings"
 license = "MIT"
-edition = "2021"
+edition = "2021" # On Update: Update the edition of the `rustfmt` command that checks the solutions.
 
 [workspace.dependencies]
 serde = { version = "1.0.204", features = ["derive"] }

src/dev/check.rs

@@ -4,6 +4,7 @@ use std::{
     fs::{self, read_dir, OpenOptions},
     io::{self, Read, Write},
     path::{Path, PathBuf},
+    process::{Command, Stdio},
     sync::atomic::{self, AtomicBool},
     thread,
 };
@@ -224,7 +225,7 @@ fn check_solutions(
     cmd_runner: &CmdRunner,
 ) -> Result<()> {
     println!("Running all solutions. This may take a while…\n");
-    let sol_paths = thread::scope(|s| {
+    thread::scope(|s| {
         let handles = info_file
             .exercises
             .iter()
@@ -250,6 +251,14 @@ fn check_solutions(
             .collect::<Vec<_>>();
 
         let mut sol_paths = hashbrown::HashSet::with_capacity(info_file.exercises.len());
+        let mut fmt_cmd = Command::new("rustfmt");
+        fmt_cmd
+            .arg("--check")
+            .arg("--edition")
+            .arg("2021")
+            .arg("--color")
+            .arg("--always")
+            .stdin(Stdio::null());
 
         for (exercise_name, handle) in info_file
             .exercises
@@ -259,6 +268,7 @@ fn check_solutions(
         {
             match handle.join() {
                 Ok(SolutionCheck::Success { sol_path }) => {
+                    fmt_cmd.arg(&sol_path);
                     sol_paths.insert(PathBuf::from(sol_path));
                 }
                 Ok(SolutionCheck::MissingRequired) => {
@@ -276,12 +286,18 @@ fn check_solutions(
             }
         }
 
-        Ok(sol_paths)
-    })?;
+        let handle = s.spawn(move || check_unexpected_files("solutions", &sol_paths));
 
-    check_unexpected_files("solutions", &sol_paths)?;
+        if !fmt_cmd
+            .status()
+            .context("Failed to run `rustfmt` on all solution files")?
+            .success()
+        {
+            bail!("Some solutions aren't formatted. Run `rustfmt` on them");
+        }
 
-    Ok(())
+        handle.join().unwrap()
+    })
 }
 
 pub fn check(require_solutions: bool) -> Result<()> {