Port tests/run-make/sysroot-crates-are-unstable from Python to rmake

src/tools/compiletest/src/runtest.rs

@@ -3588,6 +3588,7 @@ impl<'test> TestCx<'test> {
             .env("TARGET", &self.config.target)
             .env("PYTHON", &self.config.python)
             .env("SOURCE_ROOT", &src_root)
+            .env("SYSROOT_BASE", &self.config.sysroot_base)
             .env("RUST_BUILD_STAGE", &self.config.stage_id)
             .env("RUSTC", cwd.join(&self.config.rustc_path))
             .env("HOST_RPATH_DIR", cwd.join(&self.config.compile_lib_path))

src/tools/run-make-support/src/command.rs

@@ -116,6 +116,11 @@ impl Command {
         output
     }
 
+    #[track_caller]
+    pub fn run_unchecked(&mut self) -> CompletedProcess {
+        self.command_output()
+    }
+
     #[track_caller]
     fn command_output(&mut self) -> CompletedProcess {
         self.drop_bomb.defuse();

src/tools/run-make-support/src/lib.rs

@@ -280,7 +280,7 @@ pub fn recursive_diff(dir1: impl AsRef<Path>, dir2: impl AsRef<Path>) {
     });
 }
 
-pub fn read_dir<F: Fn(&Path)>(dir: impl AsRef<Path>, callback: F) {
+pub fn read_dir(dir: impl AsRef<Path>, mut callback: impl FnMut(&Path)) {
     for entry in fs::read_dir(dir).unwrap() {
         callback(&entry.unwrap().path());
     }
@@ -410,6 +410,17 @@ macro_rules! impl_common_helpers {
                 self.cmd.run_fail()
             }
 
+            /// Run the constructed command, but don't check its result status.
+            /// The caller is responsible for performing any necessary checks.
+            ///
+            /// Prefer to call [`run`](Self::run) or [`run_fail`](Self::run_fail)
+            /// if possible.
+            #[must_use]
+            #[track_caller]
+            pub fn run_unchecked(&mut self) -> crate::command::CompletedProcess {
+                self.cmd.run_unchecked()
+            }
+
             /// Set the path where the command will be run.
             pub fn current_dir<P: AsRef<::std::path::Path>>(&mut self, path: P) -> &mut Self {
                 self.cmd.current_dir(path);

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -234,7 +234,6 @@ run-make/symbols-include-type-name/Makefile
 run-make/symlinked-extern/Makefile
 run-make/symlinked-libraries/Makefile
 run-make/symlinked-rlib/Makefile
-run-make/sysroot-crates-are-unstable/Makefile
 run-make/target-cpu-native/Makefile
 run-make/target-specs/Makefile
 run-make/target-without-atomic-cas/Makefile

tests/run-make/sysroot-crates-are-unstable/rmake.rs

@@ -0,0 +1,105 @@
+//! Checks that all unstable library crates in the sysroot are actually treated
+//! as unstable.
+#![deny(warnings)]
+
+use run_make_support::{env_var, read_dir, rustc};
+use std::path::{Path, PathBuf};
+use std::str;
+
+#[derive(Debug)]
+struct Lib {
+    name: String,
+    path: PathBuf,
+}
+
+fn check_lib(lib: &Lib) -> Result<(), ()> {
+    let Lib { name, path } = lib;
+
+    println!("verifying that sysroot crate '{name}' is an unstable crate");
+
+    let output = rustc()
+        .input("-")
+        .crate_type("rlib")
+        .target(&env_var("TARGET"))
+        .extern_(name, path)
+        .stdin(format!("extern crate {name};"))
+        .run_unchecked();
+
+    if !output.status().success()
+        && output.stderr_utf8().contains("use of unstable library feature")
+    {
+        return Ok(());
+    }
+
+    eprintln!();
+    eprintln!("CRATE IS NOT UNSTABLE: `{name}` at {path:?}");
+    eprintln!("output status: `{}`", output.status());
+    eprintln!("=== STDOUT ===");
+    eprint!("{}", output.stdout_utf8());
+    eprintln!("==============");
+    eprintln!("=== STDERR ===");
+    eprint!("{}", output.stderr_utf8());
+    eprintln!("==============");
+
+    Err(())
+}
+
+fn get_all_libs(libs_dir: &Path) -> Vec<Lib> {
+    let mut libs = vec![];
+    read_dir(libs_dir, |file| {
+        if !file.is_file() {
+            return;
+        };
+
+        // Treat a file as a library if it begins with `lib` and ends with `.rlib`.
+        // The library name is the part before the first hyphen (if any).
+        // FIXME: Use a `try` block once they're stable.
+        let Some(lib_name) = Some(file).and_then(|file| {
+            file.file_name()?
+                .to_str()?
+                .strip_prefix("lib")?
+                .strip_suffix(".rlib")?
+                .split('-')
+                .next()
+        }) else {
+            return;
+        };
+
+        libs.push(Lib { name: lib_name.to_owned(), path: file.to_owned() });
+    });
+    libs
+}
+
+fn is_stable_crate(name: &str) -> bool {
+    matches!(name, "std" | "alloc" | "core" | "proc_macro")
+}
+
+fn main() {
+    // Generate a list of all library crates in the sysroot.
+    let sysroot_libs_dir = PathBuf::from(env_var("SYSROOT_BASE"))
+        .join("lib/rustlib")
+        .join(env_var("TARGET"))
+        .join("lib");
+    let sysroot_libs = get_all_libs(&sysroot_libs_dir);
+
+    // Self-check: If we didn't find `core`, we probably checked the wrong directory.
+    assert!(
+        sysroot_libs.iter().any(|lib| lib.name == "core"),
+        "couldn't find `core` in {sysroot_libs_dir:?}:\n{sysroot_libs:#?}"
+    );
+
+    let unstable_sysroot_libs =
+        sysroot_libs.iter().filter(|lib| !is_stable_crate(&lib.name)).collect::<Vec<_>>();
+    // Self-check: There should be at least one unstable lib in the directory.
+    assert!(
+        !unstable_sysroot_libs.is_empty(),
+        "couldn't find any unstable libs in {sysroot_libs_dir:?}:\n{sysroot_libs:#?}"
+    );
+
+    // Check all of the crates before actually failing, so that we report all
+    // errors instead of just the first one.
+    let results = unstable_sysroot_libs.iter().map(|lib| check_lib(lib)).collect::<Vec<_>>();
+    if results.iter().any(|r| r.is_err()) {
+        std::process::exit(1);
+    }
+}