Auto merge of rust-lang#12999 - ehuss:fix-clippy-wrapper-race, r=epage

Fix clippy-wrapper test race condition.

This fixes an issue where if certain tests ran concurrently, they would stomp on each other writing to a global directory. The problem is that `wrapped_clippy_driver` was writing to a global directory without any locking. The solution is to use the existing locking setup we have for supporting similar global tools.

This doesn't often show up because the offending tests are usually separated enough alphabetically, but if they happen to run near each other, they would stomp on each other and corrupt the directory.

crates/cargo-test-support/src/lib.rs

@@ -523,29 +523,6 @@ pub fn cargo_exe() -> PathBuf {
     snapbox::cmd::cargo_bin("cargo")
 }
 
-/// A wrapper around `rustc` instead of calling `clippy`.
-pub fn wrapped_clippy_driver() -> PathBuf {
-    let clippy_driver = project()
-        .at(paths::global_root().join("clippy-driver"))
-        .file("Cargo.toml", &basic_manifest("clippy-driver", "0.0.1"))
-        .file(
-            "src/main.rs",
-            r#"
-            fn main() {
-                let mut args = std::env::args_os();
-                let _me = args.next().unwrap();
-                let rustc = args.next().unwrap();
-                let status = std::process::Command::new(rustc).args(args).status().unwrap();
-                std::process::exit(status.code().unwrap_or(1));
-            }
-            "#,
-        )
-        .build();
-    clippy_driver.cargo("build").run();
-
-    clippy_driver.bin("clippy-driver")
-}
-
 /// This is the raw output from the process.
 ///
 /// This is similar to `std::process::Output`, however the `status` is

crates/cargo-test-support/src/tools.rs

@@ -7,6 +7,7 @@ use std::sync::OnceLock;
 
 static ECHO_WRAPPER: OnceLock<Mutex<Option<PathBuf>>> = OnceLock::new();
 static ECHO: OnceLock<Mutex<Option<PathBuf>>> = OnceLock::new();
+static CLIPPY_DRIVER: OnceLock<Mutex<Option<PathBuf>>> = OnceLock::new();
 
 /// Returns the path to an executable that works as a wrapper around rustc.
 ///
@@ -107,3 +108,34 @@ pub fn echo_subcommand() -> Project {
     p.cargo("build").run();
     p
 }
+
+/// A wrapper around `rustc` instead of calling `clippy`.
+pub fn wrapped_clippy_driver() -> PathBuf {
+    let mut lock = CLIPPY_DRIVER
+        .get_or_init(|| Default::default())
+        .lock()
+        .unwrap();
+    if let Some(path) = &*lock {
+        return path.clone();
+    }
+    let clippy_driver = project()
+        .at(paths::global_root().join("clippy-driver"))
+        .file("Cargo.toml", &basic_manifest("clippy-driver", "0.0.1"))
+        .file(
+            "src/main.rs",
+            r#"
+            fn main() {
+                let mut args = std::env::args_os();
+                let _me = args.next().unwrap();
+                let rustc = args.next().unwrap();
+                let status = std::process::Command::new(rustc).args(args).status().unwrap();
+                std::process::exit(status.code().unwrap_or(1));
+            }
+            "#,
+        )
+        .build();
+    clippy_driver.cargo("build").run();
+    let path = clippy_driver.bin("clippy-driver");
+    *lock = Some(path.clone());
+    path
+}

tests/testsuite/check.rs

@@ -6,8 +6,8 @@ use crate::messages::raw_rustc_output;
 use cargo_test_support::install::exe;
 use cargo_test_support::paths::CargoPathExt;
 use cargo_test_support::registry::Package;
+use cargo_test_support::tools;
 use cargo_test_support::{basic_bin_manifest, basic_manifest, git, project};
-use cargo_test_support::{tools, wrapped_clippy_driver};
 
 #[cargo_test]
 fn check_success() {
@@ -1432,7 +1432,7 @@ fn check_fixable_warning_for_clippy() {
 
     foo.cargo("check")
         // We can't use `clippy` so we use a `rustc` workspace wrapper instead
-        .env("RUSTC_WORKSPACE_WRAPPER", wrapped_clippy_driver())
+        .env("RUSTC_WORKSPACE_WRAPPER", tools::wrapped_clippy_driver())
         .with_stderr_contains("[..] (run `cargo clippy --fix --lib -p foo` to apply 1 suggestion)")
         .run();
 }

tests/testsuite/fix.rs

@@ -5,8 +5,8 @@ use cargo_test_support::compare::assert_match_exact;
 use cargo_test_support::git::{self, init};
 use cargo_test_support::paths::{self, CargoPathExt};
 use cargo_test_support::registry::{Dependency, Package};
+use cargo_test_support::tools;
 use cargo_test_support::{basic_manifest, is_nightly, project, Project};
-use cargo_test_support::{tools, wrapped_clippy_driver};
 
 #[cargo_test]
 fn do_not_fix_broken_builds() {
@@ -193,7 +193,7 @@ fn broken_clippy_fixes_backed_out() {
         .env("__CARGO_FIX_YOLO", "1")
         .env("RUSTC", p.root().join("foo/target/debug/foo"))
         //  We can't use `clippy` so we use a `rustc` workspace wrapper instead
-        .env("RUSTC_WORKSPACE_WRAPPER", wrapped_clippy_driver())
+        .env("RUSTC_WORKSPACE_WRAPPER", tools::wrapped_clippy_driver())
         .with_stderr_contains(
             "warning: failed to automatically apply fixes suggested by rustc \
              to crate `bar`\n\