Rollup merge of #134659 - jieyouxu:recursive-remove, r=ChrisDenton

test-infra: improve compiletest and run-make-support symlink handling

I was trying to implement #134656 to port `tests/run-make/incr-add-rust-src-component.rs`, but found some blockers related to symlink handling, so in this PR I tried to resolve them by improving symlink handling in compiletest and run-make-support (particularly for native windows msvc environment).

Key changes:

- I needed to copy symlinks (duplicate a symlink pointing to the same file), so I pulled out the copy symlink logic and re-exposed it as `run_make_support::rfs::copy_symlink`. This helper correctly accounts for the Windows symlink-to-file vs symlink-to-dir distinction (hereafter "Windows symlinks") when copying symlinks.
- `recursive_remove`:
    - I needed a way to remove symlinks themselves (no symlink traversal). `std::fs::remove_dir_all` handles them, but only if the root path is a directory. So I wrapped `std::fs::remove_dir_all` to also handle when the root path is a non-directory entity (e.g. file or symlink). Again, this properly accounts for Windows symlinks.
    - I wanted to use this for both compiletest and run-make-support, so I put the implementation and accompanying tests in `build_helper`.
    - In this sense, it's a reland of #129302 with proper test coverage.
    - It's a thin wrapper around `std::fs::remove_dir_all` (`remove_dir_all` correctly handles read-only entries on Windows). The helper has additional permission-setting logic for when the root path is a non-dir entry on Windows to handle read-only non-dir entry.

Fixes #126334.

4 files changed, 68 insertions, 56 deletions

diff --git a/src/tools/compiletest/Cargo.toml b/src/tools/compiletest/Cargo.toml
index b784bdb7139..16cc1d2a565 100644
--- a/src/tools/compiletest/Cargo.toml
+++ b/src/tools/compiletest/Cargo.toml
@@ -16,7 +16,7 @@ indexmap = "2.0.0"
 miropt-test-tools = { path = "../miropt-test-tools" }
 build_helper = { path = "../../build_helper" }
 tracing = "0.1"
-tracing-subscriber = { version = "0.3.3", default-features = false, features = ["fmt", "env-filter", "smallvec", "parking_lot", "ansi"] }
+tracing-subscriber = { version = "0.3.3", default-features = false, features = ["ansi", "env-filter", "fmt", "parking_lot", "smallvec"] }
 regex = "1.0"
 semver = { version = "1.0.23", features = ["serde"] }
 serde = { version = "1.0", features = ["derive"] }
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 6a4f0b96bb4..108fde1c899 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -2809,29 +2809,6 @@ impl<'test> TestCx<'test> {
             println!("init_incremental_test: incremental_dir={}", incremental_dir.display());
         }
     }
-
-    fn aggressive_rm_rf(&self, path: &Path) -> io::Result<()> {
-        for e in path.read_dir()? {
-            let entry = e?;
-            let path = entry.path();
-            if entry.file_type()?.is_dir() {
-                self.aggressive_rm_rf(&path)?;
-            } else {
-                // Remove readonly files as well on windows (by default we can't)
-                fs::remove_file(&path).or_else(|e| {
-                    if cfg!(windows) && e.kind() == io::ErrorKind::PermissionDenied {
-                        let mut meta = entry.metadata()?.permissions();
-                        meta.set_readonly(false);
-                        fs::set_permissions(&path, meta)?;
-                        fs::remove_file(&path)
-                    } else {
-                        Err(e)
-                    }
-                })?;
-            }
-        }
-        fs::remove_dir(path)
-    }
 }
 
 struct ProcArgs {
diff --git a/src/tools/compiletest/src/runtest/run_make.rs b/src/tools/compiletest/src/runtest/run_make.rs
index 85ade5b727a..ee7aed2a39c 100644
--- a/src/tools/compiletest/src/runtest/run_make.rs
+++ b/src/tools/compiletest/src/runtest/run_make.rs
@@ -2,6 +2,8 @@ use std::path::Path;
 use std::process::{Command, Output, Stdio};
 use std::{env, fs};
 
+use build_helper::fs::{ignore_not_found, recursive_remove};
+
 use super::{ProcRes, TestCx, disable_error_reporting};
 use crate::util::{copy_dir_all, dylib_env_var};
 
@@ -27,9 +29,8 @@ impl TestCx<'_> {
         // are hopefully going away, it seems safer to leave this perilous code
         // as-is until it can all be deleted.
         let tmpdir = cwd.join(self.output_base_name());
-        if tmpdir.exists() {
-            self.aggressive_rm_rf(&tmpdir).unwrap();
-        }
+        ignore_not_found(|| recursive_remove(&tmpdir)).unwrap();
+
         fs::create_dir_all(&tmpdir).unwrap();
 
         let host = &self.config.host;
@@ -218,9 +219,8 @@ impl TestCx<'_> {
         //
         // This setup intentionally diverges from legacy Makefile run-make tests.
         let base_dir = self.output_base_dir();
-        if base_dir.exists() {
-            self.aggressive_rm_rf(&base_dir).unwrap();
-        }
+        ignore_not_found(|| recursive_remove(&base_dir)).unwrap();
+
         let rmake_out_dir = base_dir.join("rmake_out");
         fs::create_dir_all(&rmake_out_dir).unwrap();
 
diff --git a/src/tools/run-make-support/src/fs.rs b/src/tools/run-make-support/src/fs.rs
index 2ca55ad3b3a..7ebe4a9ca13 100644
--- a/src/tools/run-make-support/src/fs.rs
+++ b/src/tools/run-make-support/src/fs.rs
@@ -1,7 +1,51 @@
+use std::fs::FileType;
 use std::io;
 use std::path::{Path, PathBuf};
 
-/// Copy a directory into another.
+/// Given a symlink at `src`, read its target, then create a new symlink at `dst` also pointing to
+/// target.
+pub fn copy_symlink(src: impl AsRef<Path>, dst: impl AsRef<Path>) {
+    let src = src.as_ref();
+    let dst = dst.as_ref();
+    let metadata = symlink_metadata(src);
+    if let Err(e) = copy_symlink_raw(metadata.file_type(), src, dst) {
+        panic!("failed to copy symlink from `{}` to `{}`: {e}", src.display(), dst.display(),);
+    }
+}
+
+fn copy_symlink_raw(ty: FileType, src: impl AsRef<Path>, dst: impl AsRef<Path>) -> io::Result<()> {
+    // Traverse symlink once to find path of target entity.
+    let target_path = std::fs::read_link(src)?;
+
+    let new_symlink_path = dst.as_ref();
+    #[cfg(windows)]
+    {
+        use std::os::windows::fs::FileTypeExt;
+        if ty.is_symlink_dir() {
+            std::os::windows::fs::symlink_dir(&target_path, new_symlink_path)?;
+        } else {
+            // Target may be a file or another symlink, in any case we can use
+            // `symlink_file` here.
+            std::os::windows::fs::symlink_file(&target_path, new_symlink_path)?;
+        }
+    }
+    #[cfg(unix)]
+    {
+        let _ = ty;
+        std::os::unix::fs::symlink(target_path, new_symlink_path)?;
+    }
+    #[cfg(not(any(windows, unix)))]
+    {
+        let _ = ty;
+        // Technically there's also wasi, but I have no clue about wasi symlink
+        // semantics and which wasi targets / environment support symlinks.
+        unimplemented!("unsupported target");
+    }
+    Ok(())
+}
+
+/// Copy a directory into another. This will not traverse symlinks; instead, it will create new
+/// symlinks pointing at target paths that symlinks in the original directory points to.
 pub fn copy_dir_all(src: impl AsRef<Path>, dst: impl AsRef<Path>) {
     fn copy_dir_all_inner(src: impl AsRef<Path>, dst: impl AsRef<Path>) -> io::Result<()> {
         let dst = dst.as_ref();
@@ -14,31 +58,7 @@ pub fn copy_dir_all(src: impl AsRef<Path>, dst: impl AsRef<Path>) {
             if ty.is_dir() {
                 copy_dir_all_inner(entry.path(), dst.join(entry.file_name()))?;
             } else if ty.is_symlink() {
-                // Traverse symlink once to find path of target entity.
-                let target_path = std::fs::read_link(entry.path())?;
-
-                let new_symlink_path = dst.join(entry.file_name());
-                #[cfg(windows)]
-                {
-                    use std::os::windows::fs::FileTypeExt;
-                    if ty.is_symlink_dir() {
-                        std::os::windows::fs::symlink_dir(&target_path, new_symlink_path)?;
-                    } else {
-                        // Target may be a file or another symlink, in any case we can use
-                        // `symlink_file` here.
-                        std::os::windows::fs::symlink_file(&target_path, new_symlink_path)?;
-                    }
-                }
-                #[cfg(unix)]
-                {
-                    std::os::unix::fs::symlink(target_path, new_symlink_path)?;
-                }
-                #[cfg(not(any(windows, unix)))]
-                {
-                    // Technically there's also wasi, but I have no clue about wasi symlink
-                    // semantics and which wasi targets / environment support symlinks.
-                    unimplemented!("unsupported target");
-                }
+                copy_symlink_raw(ty, entry.path(), dst.join(entry.file_name()))?;
             } else {
                 std::fs::copy(entry.path(), dst.join(entry.file_name()))?;
             }
@@ -64,6 +84,21 @@ pub fn read_dir_entries<P: AsRef<Path>, F: FnMut(&Path)>(dir: P, mut callback: F
     }
 }
 
+/// A wrapper around [`build_helper::fs::recursive_remove`] which includes the file path in the
+/// panic message.
+///
+/// This handles removing symlinks on Windows (e.g. symlink-to-file will be removed via
+/// [`std::fs::remove_file`] while symlink-to-dir will be removed via [`std::fs::remove_dir`]).
+#[track_caller]
+pub fn recursive_remove<P: AsRef<Path>>(path: P) {
+    if let Err(e) = build_helper::fs::recursive_remove(path.as_ref()) {
+        panic!(
+            "failed to recursive remove filesystem entities at `{}`: {e}",
+            path.as_ref().display()
+        );
+    }
+}
+
 /// A wrapper around [`std::fs::remove_file`] which includes the file path in the panic message.
 #[track_caller]
 pub fn remove_file<P: AsRef<Path>>(path: P) {