Rollup merge of #129152 - onur-ozkan:custom-clippy, r=Kobzol

custom/external clippy support for bootstrapping

Similar to cargo, rustc, and rustfmt, this adds the support of using custom clippy on bootstrap. It’s designed for those who want to test their own clippy builds or avoid downloading the stage0 clippy.

Closes #121518

3 files changed, 22 insertions, 2 deletions

diff --git a/src/bootstrap/src/core/builder.rs b/src/bootstrap/src/core/builder.rs
index ff0d1f3a725..d7398b76cc9 100644
--- a/src/bootstrap/src/core/builder.rs
+++ b/src/bootstrap/src/core/builder.rs
@@ -1298,8 +1298,12 @@ impl<'a> Builder<'a> {
 
     pub fn cargo_clippy_cmd(&self, run_compiler: Compiler) -> BootstrapCommand {
         if run_compiler.stage == 0 {
-            // `ensure(Clippy { stage: 0 })` *builds* clippy with stage0, it doesn't use the beta clippy.
-            let cargo_clippy = self.build.config.download_clippy();
+            let cargo_clippy = self
+                .config
+                .initial_cargo_clippy
+                .clone()
+                .unwrap_or_else(|| self.build.config.download_clippy());
+
             let mut cmd = command(cargo_clippy);
             cmd.env("CARGO", &self.initial_cargo);
             return cmd;
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index bdfee55d8d1..fba80b92f45 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -344,6 +344,7 @@ pub struct Config {
     // These are either the stage0 downloaded binaries or the locally installed ones.
     pub initial_cargo: PathBuf,
     pub initial_rustc: PathBuf,
+    pub initial_cargo_clippy: Option<PathBuf>,
 
     #[cfg(not(test))]
     initial_rustfmt: RefCell<RustfmtState>,
@@ -834,6 +835,7 @@ define_config! {
         cargo: Option<PathBuf> = "cargo",
         rustc: Option<PathBuf> = "rustc",
         rustfmt: Option<PathBuf> = "rustfmt",
+        cargo_clippy: Option<PathBuf> = "cargo-clippy",
         docs: Option<bool> = "docs",
         compiler_docs: Option<bool> = "compiler-docs",
         library_docs_private_items: Option<bool> = "library-docs-private-items",
@@ -1439,6 +1441,7 @@ impl Config {
             cargo,
             rustc,
             rustfmt,
+            cargo_clippy,
             docs,
             compiler_docs,
             library_docs_private_items,
@@ -1491,6 +1494,14 @@ impl Config {
             config.out = absolute(&config.out).expect("can't make empty path absolute");
         }
 
+        if cargo_clippy.is_some() && rustc.is_none() {
+            println!(
+                "WARNING: Using `build.cargo-clippy` without `build.rustc` usually fails due to toolchain conflict."
+            );
+        }
+
+        config.initial_cargo_clippy = cargo_clippy;
+
         config.initial_rustc = if let Some(rustc) = rustc {
             if !flags.skip_stage0_validation {
                 config.check_stage0_version(&rustc, "rustc");
diff --git a/src/bootstrap/src/utils/change_tracker.rs b/src/bootstrap/src/utils/change_tracker.rs
index 51a25104e4c..3ab14aade9f 100644
--- a/src/bootstrap/src/utils/change_tracker.rs
+++ b/src/bootstrap/src/utils/change_tracker.rs
@@ -235,4 +235,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Info,
         summary: "The `build.profiler` option now tries to use source code from `download-ci-llvm` if possible, instead of checking out the `src/llvm-project` submodule.",
     },
+    ChangeInfo {
+        change_id: 129152,
+        severity: ChangeSeverity::Info,
+        summary: "New option `build.cargo-clippy` added for supporting the use of custom/external clippy.",
+    },
 ];