Remove rust-toolchain before running builds

This avoids running with the wrong version of the toolchain.

Author: jyn514

src/prepare.rs

@@ -38,7 +38,7 @@ impl<'a> Prepare<'a> {
     pub(crate) fn prepare(&mut self) -> Result<(), Error> {
         self.krate.copy_source_to(self.workspace, self.source_dir)?;
         self.validate_manifest()?;
-        self.remove_cargo_config()?;
+        self.remove_override_files()?;
         self.tweak_toml()?;
         self.capture_lockfile(false)?;
         self.fetch_deps()?;
@@ -69,11 +69,17 @@ impl<'a> Prepare<'a> {
         Ok(())
     }
 
-    fn remove_cargo_config(&self) -> Result<(), Error> {
-        let path = self.source_dir.join(".cargo").join("config");
-        if path.exists() {
-            crate::utils::remove_file(&path)?;
-            info!("removed {}", path.display());
+    fn remove_override_files(&self) -> Result<(), Error> {
+        let paths = [
+            &Path::new(".cargo").join("config"),
+            Path::new("rust-toolchain"),
+        ];
+        for path in &paths {
+            let path = self.source_dir.join(path);
+            if path.exists() {
+                crate::utils::remove_file(&path)?;
+                info!("removed {}", path.display());
+            }
         }
         Ok(())
     }

tests/buildtest/crates/cargo-config/rust-toolchain

@@ -0,0 +1 @@
+1.0.0

tests/buildtest/mod.rs

@@ -83,14 +83,18 @@ fn test_sandbox_oom() {
 }
 
 #[test]
-fn test_cargo_config() {
+fn test_override_files() {
     runner::run("cargo-config", |run| {
         run.build(SandboxBuilder::new().enable_networking(false), |build| {
             let storage = rustwide::logging::LogStorage::new(LevelFilter::Info);
             rustwide::logging::capture(&storage, || -> Result<_, Error> {
-                build.cargo().args(&["run"]).run()?;
+                build.cargo().args(&["--version"]).run()?;
                 Ok(())
             })?;
+            let output = storage.to_string();
+            assert!(output.contains("cargo 1."));
+            assert!(!output.contains("1.0.0"));
+            build.cargo().args(&["run"]).run()?;
             Ok(())
         })?;
         Ok(())