Use Cargo instead of rustc

src/exercise.rs

@@ -1,21 +1,21 @@
+use anyhow::{Context, Result};
 use serde::Deserialize;
-use std::fmt::{self, Display, Formatter};
-use std::fs::{self, remove_file, File};
+use std::fmt::{self, Debug, Display, Formatter};
+use std::fs::{self, File};
 use std::io::{self, BufRead, BufReader};
 use std::path::PathBuf;
-use std::process::{self, exit, Command, Stdio};
-use std::{array, env, mem};
+use std::process::{exit, Command, Output};
+use std::{array, mem};
 use winnow::ascii::{space0, Caseless};
 use winnow::combinator::opt;
 use winnow::Parser;
 
-const RUSTC_COLOR_ARGS: &[&str] = &["--color", "always"];
-const RUSTC_EDITION_ARGS: &[&str] = &["--edition", "2021"];
-const RUSTC_NO_DEBUG_ARGS: &[&str] = &["-C", "strip=debuginfo"];
-const CONTEXT: usize = 2;
-const CLIPPY_CARGO_TOML_PATH: &str = "exercises/22_clippy/Cargo.toml";
+use crate::embedded::EMBEDDED_FILES;
 
-// Checks if the line contains the "I AM NOT DONE" comment.
+// The number of context lines above and below a highlighted line.
+const CONTEXT: usize = 2;
+
+// Check if the line contains the "I AM NOT DONE" comment.
 fn contains_not_done_comment(input: &str) -> bool {
     (
         space0::<_, ()>,
@@ -28,26 +28,15 @@ fn contains_not_done_comment(input: &str) -> bool {
         .is_ok()
 }
 
-// Get a temporary file name that is hopefully unique
-#[inline]
-fn temp_file() -> String {
-    let thread_id: String = format!("{:?}", std::thread::current().id())
-        .chars()
-        .filter(|c| c.is_alphanumeric())
-        .collect();
-
-    format!("./temp_{}_{thread_id}", process::id())
-}
-
 // The mode of the exercise.
-#[derive(Deserialize, Copy, Clone, Debug)]
+#[derive(Deserialize, Copy, Clone)]
 #[serde(rename_all = "lowercase")]
 pub enum Mode {
-    // Indicates that the exercise should be compiled as a binary
+    // The exercise should be compiled as a binary
     Compile,
-    // Indicates that the exercise should be compiled as a test harness
+    // The exercise should be compiled as a test harness
     Test,
-    // Indicates that the exercise should be linted with clippy
+    // The exercise should be linted with clippy
     Clippy,
 }
 
@@ -56,171 +45,72 @@ pub struct ExerciseList {
     pub exercises: Vec<Exercise>,
 }
 
-// A representation of a rustlings exercise.
-// This is deserialized from the accompanying info.toml file
-#[derive(Deserialize, Debug)]
+impl ExerciseList {
+    pub fn parse() -> Result<Self> {
+        // Read a local `info.toml` if it exists.
+        // Mainly to let the tests work for now.
+        if let Ok(file_content) = fs::read_to_string("info.toml") {
+            toml_edit::de::from_str(&file_content)
+        } else {
+            toml_edit::de::from_str(EMBEDDED_FILES.info_toml_content)
+        }
+        .context("Failed to parse `info.toml`")
+    }
+}
+
+// Deserialized from the `info.toml` file.
+#[derive(Deserialize)]
 pub struct Exercise {
     // Name of the exercise
     pub name: String,
     // The path to the file containing the exercise's source code
     pub path: PathBuf,
-    // The mode of the exercise (Test, Compile, or Clippy)
+    // The mode of the exercise
     pub mode: Mode,
     // The hint text associated with the exercise
     pub hint: String,
 }
 
-// An enum to track of the state of an Exercise.
-// An Exercise can be either Done or Pending
+// The state of an Exercise.
 #[derive(PartialEq, Eq, Debug)]
 pub enum State {
-    // The state of the exercise once it's been completed
     Done,
-    // The state of the exercise while it's not completed yet
     Pending(Vec<ContextLine>),
 }
 
-// The context information of a pending exercise
+// The context information of a pending exercise.
 #[derive(PartialEq, Eq, Debug)]
 pub struct ContextLine {
-    // The source code that is still pending completion
+    // The source code line
     pub line: String,
-    // The line number of the source code still pending completion
+    // The line number
     pub number: usize,
-    // Whether or not this is important
+    // Whether this is important and should be highlighted
     pub important: bool,
 }
 
-// The result of compiling an exercise
-pub struct CompiledExercise<'a> {
-    exercise: &'a Exercise,
-    _handle: FileHandle,
-}
-
-impl<'a> CompiledExercise<'a> {
-    // Run the compiled exercise
-    pub fn run(&self) -> Result<ExerciseOutput, ExerciseOutput> {
-        self.exercise.run()
-    }
-}
-
-// A representation of an already executed binary
-#[derive(Debug)]
-pub struct ExerciseOutput {
-    // The textual contents of the standard output of the binary
-    pub stdout: String,
-    // The textual contents of the standard error of the binary
-    pub stderr: String,
-}
-
-struct FileHandle;
-
-impl Drop for FileHandle {
-    fn drop(&mut self) {
-        clean();
-    }
-}
-
 impl Exercise {
-    pub fn compile(&self) -> Result<CompiledExercise, ExerciseOutput> {
-        let cmd = match self.mode {
-            Mode::Compile => Command::new("rustc")
-                .args([self.path.to_str().unwrap(), "-o", &temp_file()])
-                .args(RUSTC_COLOR_ARGS)
-                .args(RUSTC_EDITION_ARGS)
-                .args(RUSTC_NO_DEBUG_ARGS)
-                .output(),
-            Mode::Test => Command::new("rustc")
-                .args(["--test", self.path.to_str().unwrap(), "-o", &temp_file()])
-                .args(RUSTC_COLOR_ARGS)
-                .args(RUSTC_EDITION_ARGS)
-                .args(RUSTC_NO_DEBUG_ARGS)
-                .output(),
-            Mode::Clippy => {
-                let cargo_toml = format!(
-                    r#"[package]
-name = "{}"
-version = "0.0.1"
-edition = "2021"
-[[bin]]
-name = "{}"
-path = "{}.rs""#,
-                    self.name, self.name, self.name
-                );
-                let cargo_toml_error_msg = if env::var("NO_EMOJI").is_ok() {
-                    "Failed to write Clippy Cargo.toml file."
-                } else {
-                    "Failed to write 📎 Clippy 📎 Cargo.toml file."
-                };
-                fs::write(CLIPPY_CARGO_TOML_PATH, cargo_toml).expect(cargo_toml_error_msg);
-                // To support the ability to run the clippy exercises, build
-                // an executable, in addition to running clippy. With a
-                // compilation failure, this would silently fail. But we expect
-                // clippy to reflect the same failure while compiling later.
-                Command::new("rustc")
-                    .args([self.path.to_str().unwrap(), "-o", &temp_file()])
-                    .args(RUSTC_COLOR_ARGS)
-                    .args(RUSTC_EDITION_ARGS)
-                    .args(RUSTC_NO_DEBUG_ARGS)
-                    .stdin(Stdio::null())
-                    .stdout(Stdio::null())
-                    .stderr(Stdio::null())
-                    .status()
-                    .expect("Failed to compile!");
-                // Due to an issue with Clippy, a cargo clean is required to catch all lints.
-                // See https://github.com/rust-lang/rust-clippy/issues/2604
-                // This is already fixed on Clippy's master branch. See this issue to track merging into Cargo:
-                // https://github.com/rust-lang/rust-clippy/issues/3837
-                Command::new("cargo")
-                    .args(["clean", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
-                    .args(RUSTC_COLOR_ARGS)
-                    .stdin(Stdio::null())
-                    .stdout(Stdio::null())
-                    .stderr(Stdio::null())
-                    .status()
-                    .expect("Failed to run 'cargo clean'");
-                Command::new("cargo")
-                    .args(["clippy", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
-                    .args(RUSTC_COLOR_ARGS)
-                    .args(["--", "-D", "warnings", "-D", "clippy::float_cmp"])
-                    .output()
-            }
-        }
-        .expect("Failed to run 'compile' command.");
-
-        if cmd.status.success() {
-            Ok(CompiledExercise {
-                exercise: self,
-                _handle: FileHandle,
-            })
-        } else {
-            clean();
-            Err(ExerciseOutput {
-                stdout: String::from_utf8_lossy(&cmd.stdout).to_string(),
-                stderr: String::from_utf8_lossy(&cmd.stderr).to_string(),
-            })
-        }
+    fn cargo_cmd(&self, command: &str, args: &[&str]) -> Result<Output> {
+        Command::new("cargo")
+            .arg(command)
+            .arg("--color")
+            .arg("always")
+            .arg("-q")
+            .arg("--bin")
+            .arg(&self.name)
+            .args(args)
+            .output()
+            .context("Failed to run Cargo")
     }
 
-    fn run(&self) -> Result<ExerciseOutput, ExerciseOutput> {
-        let arg = match self.mode {
-            Mode::Test => "--show-output",
-            _ => "",
-        };
-        let cmd = Command::new(temp_file())
-            .arg(arg)
-            .output()
-            .expect("Failed to run 'run' command");
-
-        let output = ExerciseOutput {
-            stdout: String::from_utf8_lossy(&cmd.stdout).to_string(),
-            stderr: String::from_utf8_lossy(&cmd.stderr).to_string(),
-        };
-
-        if cmd.status.success() {
-            Ok(output)
-        } else {
-            Err(output)
+    pub fn run(&self) -> Result<Output> {
+        match self.mode {
+            Mode::Compile => self.cargo_cmd("run", &[]),
+            Mode::Test => self.cargo_cmd("test", &["--", "--nocapture"]),
+            Mode::Clippy => self.cargo_cmd(
+                "clippy",
+                &["--", "-D", "warnings", "-D", "clippy::float_cmp"],
+            ),
         }
     }
 
@@ -335,51 +225,13 @@ path = "{}.rs""#,
 
 impl Display for Exercise {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{}", self.path.to_str().unwrap())
+        self.path.fmt(f)
     }
 }
 
-#[inline]
-fn clean() {
-    let _ignored = remove_file(temp_file());
-}
-
 #[cfg(test)]
 mod test {
     use super::*;
-    use std::path::Path;
-
-    #[test]
-    fn test_clean() {
-        File::create(temp_file()).unwrap();
-        let exercise = Exercise {
-            name: String::from("example"),
-            path: PathBuf::from("tests/fixture/state/exercises/pending_exercise.rs"),
-            mode: Mode::Compile,
-            hint: String::from(""),
-        };
-        let compiled = exercise.compile().unwrap();
-        drop(compiled);
-        assert!(!Path::new(&temp_file()).exists());
-    }
-
-    #[test]
-    #[cfg(target_os = "windows")]
-    fn test_no_pdb_file() {
-        [Mode::Compile, Mode::Test] // Clippy doesn't like to test
-            .iter()
-            .for_each(|mode| {
-                let exercise = Exercise {
-                    name: String::from("example"),
-                    // We want a file that does actually compile
-                    path: PathBuf::from("tests/fixture/state/exercises/pending_exercise.rs"),
-                    mode: *mode,
-                    hint: String::from(""),
-                };
-                let _ = exercise.compile().unwrap();
-                assert!(!Path::new(&format!("{}.pdb", temp_file())).exists());
-            });
-    }
 
     #[test]
     fn test_pending_state() {
@@ -442,8 +294,8 @@ mod test {
             mode: Mode::Test,
             hint: String::new(),
         };
-        let out = exercise.compile().unwrap().run().unwrap();
-        assert!(out.stdout.contains("THIS TEST TOO SHALL PASS"));
+        let out = exercise.run().unwrap();
+        assert_eq!(out.stdout, b"THIS TEST TOO SHALL PASS");
     }
 
     #[test]

src/main.rs

@@ -4,20 +4,18 @@ use crate::verify::verify;
 use anyhow::{Context, Result};
 use clap::{Parser, Subcommand};
 use console::Emoji;
-use embedded::EMBEDDED_FILES;
 use notify_debouncer_mini::notify::{self, RecursiveMode};
 use notify_debouncer_mini::{new_debouncer, DebouncedEventKind};
 use shlex::Shlex;
 use std::ffi::OsStr;
-use std::fs;
-use std::io::{self, prelude::*};
+use std::io::{BufRead, Write};
 use std::path::Path;
 use std::process::{exit, Command};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::{channel, RecvTimeoutError};
 use std::sync::{Arc, Mutex};
-use std::thread;
 use std::time::Duration;
+use std::{io, thread};
 
 #[macro_use]
 mod ui;
@@ -94,21 +92,16 @@ fn main() -> Result<()> {
         println!("\n{WELCOME}\n");
     }
 
-    if which::which("rustc").is_err() {
-        println!("We cannot find `rustc`.");
-        println!("Try running `rustc --version` to diagnose your problem.");
-        println!("For instructions on how to install Rust, check the README.");
+    if which::which("cargo").is_err() {
+        println!(
+            "Failed to find `cargo`.
+Did you already install Rust?
+Try running `cargo --version` to diagnose the problem."
+        );
         std::process::exit(1);
     }
 
-    // Read a local `info.toml` if it exists. Mainly to let the tests work for now.
-    let exercises = if let Ok(file_content) = fs::read_to_string("info.toml") {
-        toml_edit::de::from_str::<ExerciseList>(&file_content)
-    } else {
-        toml_edit::de::from_str::<ExerciseList>(EMBEDDED_FILES.info_toml_content)
-    }
-    .context("Failed to parse `info.toml`")?
-    .exercises;
+    let exercises = ExerciseList::parse()?.exercises;
 
     if matches!(args.command, Some(Subcommands::Init)) {
         init::init_rustlings(&exercises).context("Initialization failed")?;

src/run.rs

@@ -1,4 +1,5 @@
-use std::io;
+use anyhow::{bail, Result};
+use std::io::{self, stdout, Write};
 use std::time::Duration;
 
 use crate::embedded::{WriteStrategy, EMBEDDED_FILES};
@@ -10,13 +11,11 @@ use indicatif::ProgressBar;
 // and run the ensuing binary.
 // The verbose argument helps determine whether or not to show
 // the output from the test harnesses (if the mode of the exercise is test)
-pub fn run(exercise: &Exercise, verbose: bool) -> Result<(), ()> {
+pub fn run(exercise: &Exercise, verbose: bool) -> Result<()> {
     match exercise.mode {
-        Mode::Test => test(exercise, verbose)?,
-        Mode::Compile => compile_and_run(exercise)?,
-        Mode::Clippy => compile_and_run(exercise)?,
+        Mode::Test => test(exercise, verbose),
+        Mode::Compile | Mode::Clippy => compile_and_run(exercise),
     }
-    Ok(())
 }
 
 // Resets the exercise by stashing the changes.
@@ -27,41 +26,21 @@ pub fn reset(exercise: &Exercise) -> io::Result<()> {
 // Invoke the rust compiler on the path of the given exercise
 // and run the ensuing binary.
 // This is strictly for non-test binaries, so output is displayed
-fn compile_and_run(exercise: &Exercise) -> Result<(), ()> {
+fn compile_and_run(exercise: &Exercise) -> Result<()> {
     let progress_bar = ProgressBar::new_spinner();
-    progress_bar.set_message(format!("Compiling {exercise}..."));
+    progress_bar.set_message(format!("Running {exercise}..."));
     progress_bar.enable_steady_tick(Duration::from_millis(100));
 
-    let compilation_result = exercise.compile();
-    let compilation = match compilation_result {
-        Ok(compilation) => compilation,
-        Err(output) => {
-            progress_bar.finish_and_clear();
-            warn!(
-                "Compilation of {} failed!, Compiler error message:\n",
-                exercise
-            );
-            println!("{}", output.stderr);
-            return Err(());
-        }
-    };
-
-    progress_bar.set_message(format!("Running {exercise}..."));
-    let result = compilation.run();
+    let output = exercise.run()?;
     progress_bar.finish_and_clear();
 
-    match result {
-        Ok(output) => {
-            println!("{}", output.stdout);
-            success!("Successfully ran {}", exercise);
-            Ok(())
-        }
-        Err(output) => {
-            println!("{}", output.stdout);
-            println!("{}", output.stderr);
-
-            warn!("Ran {} with errors", exercise);
-            Err(())
-        }
+    stdout().write_all(&output.stdout)?;
+    if !output.status.success() {
+        stdout().write_all(&output.stderr)?;
+        warn!("Ran {} with errors", exercise);
+        bail!("TODO");
     }
+
+    success!("Successfully ran {}", exercise);
+    Ok(())
 }

src/verify.rs

@@ -1,7 +1,14 @@
-use crate::exercise::{CompiledExercise, Exercise, Mode, State};
+use anyhow::{bail, Result};
 use console::style;
 use indicatif::{ProgressBar, ProgressStyle};
-use std::{env, time::Duration};
+use std::{
+    env,
+    io::{stdout, Write},
+    process::Output,
+    time::Duration,
+};
+
+use crate::exercise::{Exercise, Mode, State};
 
 // Verify that the provided container of Exercise objects
 // can be compiled and run without any failures.
@@ -58,50 +65,44 @@ enum RunMode {
 }
 
 // Compile and run the resulting test harness of the given Exercise
-pub fn test(exercise: &Exercise, verbose: bool) -> Result<(), ()> {
+pub fn test(exercise: &Exercise, verbose: bool) -> Result<()> {
     compile_and_test(exercise, RunMode::NonInteractive, verbose, false)?;
     Ok(())
 }
 
 // Invoke the rust compiler without running the resulting binary
-fn compile_only(exercise: &Exercise, success_hints: bool) -> Result<bool, ()> {
+fn compile_only(exercise: &Exercise, success_hints: bool) -> Result<bool> {
     let progress_bar = ProgressBar::new_spinner();
     progress_bar.set_message(format!("Compiling {exercise}..."));
     progress_bar.enable_steady_tick(Duration::from_millis(100));
 
-    let _ = compile(exercise, &progress_bar)?;
+    let _ = exercise.run()?;
     progress_bar.finish_and_clear();
 
     Ok(prompt_for_completion(exercise, None, success_hints))
 }
 
 // Compile the given Exercise and run the resulting binary in an interactive mode
-fn compile_and_run_interactively(exercise: &Exercise, success_hints: bool) -> Result<bool, ()> {
+fn compile_and_run_interactively(exercise: &Exercise, success_hints: bool) -> Result<bool> {
     let progress_bar = ProgressBar::new_spinner();
-    progress_bar.set_message(format!("Compiling {exercise}..."));
+    progress_bar.set_message(format!("Running {exercise}..."));
     progress_bar.enable_steady_tick(Duration::from_millis(100));
 
-    let compilation = compile(exercise, &progress_bar)?;
-
-    progress_bar.set_message(format!("Running {exercise}..."));
-    let result = compilation.run();
+    let output = exercise.run()?;
     progress_bar.finish_and_clear();
 
-    let output = match result {
-        Ok(output) => output,
-        Err(output) => {
-            warn!("Ran {} with errors", exercise);
-            println!("{}", output.stdout);
-            println!("{}", output.stderr);
-            return Err(());
+    if !output.status.success() {
+        warn!("Ran {} with errors", exercise);
+        {
+            let mut stdout = stdout().lock();
+            stdout.write_all(&output.stdout)?;
+            stdout.write_all(&output.stderr)?;
+            stdout.flush()?;
         }
-    };
+        bail!("TODO");
+    }
 
-    Ok(prompt_for_completion(
-        exercise,
-        Some(output.stdout),
-        success_hints,
-    ))
+    Ok(prompt_for_completion(exercise, Some(output), success_hints))
 }
 
 // Compile the given Exercise as a test harness and display
@@ -111,62 +112,42 @@ fn compile_and_test(
     run_mode: RunMode,
     verbose: bool,
     success_hints: bool,
-) -> Result<bool, ()> {
+) -> Result<bool> {
     let progress_bar = ProgressBar::new_spinner();
     progress_bar.set_message(format!("Testing {exercise}..."));
     progress_bar.enable_steady_tick(Duration::from_millis(100));
 
-    let compilation = compile(exercise, &progress_bar)?;
-    let result = compilation.run();
+    let output = exercise.run()?;
     progress_bar.finish_and_clear();
 
-    match result {
-        Ok(output) => {
-            if verbose {
-                println!("{}", output.stdout);
-            }
-            if run_mode == RunMode::Interactive {
-                Ok(prompt_for_completion(exercise, None, success_hints))
-            } else {
-                Ok(true)
-            }
-        }
-        Err(output) => {
-            warn!(
-                "Testing of {} failed! Please try again. Here's the output:",
-                exercise
-            );
-            println!("{}", output.stdout);
-            Err(())
+    if !output.status.success() {
+        warn!(
+            "Testing of {} failed! Please try again. Here's the output:",
+            exercise
+        );
+        {
+            let mut stdout = stdout().lock();
+            stdout.write_all(&output.stdout)?;
+            stdout.write_all(&output.stderr)?;
+            stdout.flush()?;
         }
+        bail!("TODO");
     }
-}
 
-// Compile the given Exercise and return an object with information
-// about the state of the compilation
-fn compile<'a>(
-    exercise: &'a Exercise,
-    progress_bar: &ProgressBar,
-) -> Result<CompiledExercise<'a>, ()> {
-    let compilation_result = exercise.compile();
+    if verbose {
+        stdout().write_all(&output.stdout)?;
+    }
 
-    match compilation_result {
-        Ok(compilation) => Ok(compilation),
-        Err(output) => {
-            progress_bar.finish_and_clear();
-            warn!(
-                "Compiling of {} failed! Please try again. Here's the output:",
-                exercise
-            );
-            println!("{}", output.stderr);
-            Err(())
-        }
+    if run_mode == RunMode::Interactive {
+        Ok(prompt_for_completion(exercise, None, success_hints))
+    } else {
+        Ok(true)
     }
 }
 
 fn prompt_for_completion(
     exercise: &Exercise,
-    prompt_output: Option<String>,
+    prompt_output: Option<Output>,
     success_hints: bool,
 ) -> bool {
     let context = match exercise.state() {
@@ -200,10 +181,10 @@ fn prompt_for_completion(
     }
 
     if let Some(output) = prompt_output {
-        println!(
-            "Output:\n{separator}\n{output}\n{separator}\n",
-            separator = separator(),
-        );
+        let separator = separator();
+        println!("Output:\n{separator}");
+        stdout().write_all(&output.stdout).unwrap();
+        println!("\n{separator}\n");
     }
     if success_hints {
         println!(