From 598387bfb53bb6cf5edb00a5b53294b766446221 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20Ber=C3=A1nek?= <berykubik@gmail.com>
Date: Tue, 26 Aug 2025 08:52:04 +0200
Subject: [PATCH] Add snapshot test for cross-compiled dist without docs

---
 src/bootstrap/src/core/builder/mod.rs   |  3 +-
 src/bootstrap/src/core/builder/tests.rs | 90 ++++++++++++++++++++++++-
 2 files changed, 88 insertions(+), 5 deletions(-)

diff --git a/src/bootstrap/src/core/builder/mod.rs b/src/bootstrap/src/core/builder/mod.rs
index 4f1bed13c13e..76cade25a038 100644
--- a/src/bootstrap/src/core/builder/mod.rs
+++ b/src/bootstrap/src/core/builder/mod.rs
@@ -145,8 +145,7 @@ pub trait Step: 'static + Clone + Debug + PartialEq + Eq + Hash {
 }
 
 /// Metadata that describes an executed step, mostly for testing and tracing.
-#[allow(unused)]
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct StepMetadata {
     name: String,
     kind: Kind,
diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
index 5260b43f706c..46f34456a49d 100644
--- a/src/bootstrap/src/core/builder/tests.rs
+++ b/src/bootstrap/src/core/builder/tests.rs
@@ -1493,7 +1493,7 @@ mod snapshot {
     /// This also serves as an important regression test for <https://github.com/rust-lang/rust/issues/138123>
     /// and <https://github.com/rust-lang/rust/issues/138004>.
     #[test]
-    fn dist_all_cross() {
+    fn dist_all_cross_extended() {
         let ctx = TestCtx::new();
         insta::assert_snapshot!(
             ctx
@@ -1571,8 +1571,77 @@ mod snapshot {
         ");
     }
 
-    // Enable dist cranelift tarball by default with `x dist` if cranelift is enabled in
-    // `rust.codegen-backends`.
+    /// Simulates e.g. the powerpc64 builder, which is fully cross-compiled from x64, but it does
+    /// not build docs. Crutically, it shouldn't build host stage 2 rustc.
+    #[test]
+    fn dist_all_cross_extended_no_docs() {
+        let ctx = TestCtx::new();
+        let steps = ctx
+            .config("dist")
+            .hosts(&[TEST_TRIPLE_1])
+            .targets(&[TEST_TRIPLE_1])
+            .args(&[
+                "--set",
+                "rust.channel=nightly",
+                "--set",
+                "build.extended=true",
+                "--set",
+                "build.docs=false",
+            ])
+            .get_steps();
+
+        // Make sure that we don't build stage2 host rustc
+        // steps.assert_no_match(|m| {
+        //     m.name == "rustc"
+        //         && m.built_by.map(|b| b.stage) == Some(1)
+        //         && *m.target.triple == host_target()
+        // });
+
+        insta::assert_snapshot!(
+                steps.render(), @r"
+        [dist] mingw <target1>
+        [build] llvm <host>
+        [build] llvm <target1>
+        [build] rustc 0 <host> -> rustc 1 <host>
+        [build] rustc 0 <host> -> WasmComponentLd 1 <host>
+        [build] rustc 1 <host> -> std 1 <target1>
+        [build] rustc 1 <host> -> std 1 <host>
+        [build] rustc 1 <host> -> rustc 2 <target1>
+        [build] rustc 1 <host> -> WasmComponentLd 2 <target1>
+        [build] rustdoc 2 <target1>
+        [build] rustc 1 <host> -> rust-analyzer-proc-macro-srv 2 <target1>
+        [build] rustc 0 <host> -> GenerateCopyright 1 <host>
+        [build] rustc 0 <host> -> RustInstaller 1 <host>
+        [dist] rustc <target1>
+        [build] rustc 1 <host> -> rustc 2 <host>
+        [build] rustc 1 <host> -> WasmComponentLd 2 <host>
+        [build] rustc 2 <host> -> std 2 <target1>
+        [dist] rustc 2 <host> -> std 2 <target1>
+        [dist] rustc 1 <host> -> rustc-dev 2 <target1>
+        [dist] rustc 1 <host> -> analysis 2 <target1>
+        [dist] src <>
+        [build] rustc 1 <host> -> cargo 2 <target1>
+        [dist] rustc 1 <host> -> cargo 2 <target1>
+        [build] rustc 1 <host> -> rust-analyzer 2 <target1>
+        [dist] rustc 1 <host> -> rust-analyzer 2 <target1>
+        [build] rustc 1 <host> -> rustfmt 2 <target1>
+        [build] rustc 1 <host> -> cargo-fmt 2 <target1>
+        [dist] rustc 1 <host> -> rustfmt 2 <target1>
+        [build] rustc 1 <host> -> clippy-driver 2 <target1>
+        [build] rustc 1 <host> -> cargo-clippy 2 <target1>
+        [dist] rustc 1 <host> -> clippy 2 <target1>
+        [build] rustc 1 <host> -> miri 2 <target1>
+        [build] rustc 1 <host> -> cargo-miri 2 <target1>
+        [dist] rustc 1 <host> -> miri 2 <target1>
+        [build] rustc 1 <host> -> LlvmBitcodeLinker 2 <target1>
+        [dist] rustc 1 <host> -> std 1 <target1>
+        [dist] rustc 1 <host> -> extended 2 <target1>
+        [dist] reproducible-artifacts <target1>
+        ");
+    }
+
+    /// Enable dist cranelift tarball by default with `x dist` if cranelift is enabled in
+    /// `rust.codegen-backends`.
     #[test]
     fn dist_cranelift_by_default() {
         let ctx = TestCtx::new();
@@ -2426,6 +2495,21 @@ impl ExecutedSteps {
         }
     }
 
+    /// Make sure that no metadata matches the given `func`.
+    #[track_caller]
+    fn assert_no_match<F>(&self, func: F)
+    where
+        F: Fn(StepMetadata) -> bool,
+    {
+        for metadata in self.steps.iter().filter_map(|s| s.metadata.clone()) {
+            if func(metadata.clone()) {
+                panic!(
+                    "Metadata {metadata:?} was found, even though it should have not been present"
+                );
+            }
+        }
+    }
+
     fn contains(&self, metadata: &StepMetadata) -> bool {
         self.steps
             .iter()