Auto merge of #11122 - weihanglo:issue-11101, r=epage

Unlink old final artifacts before compilation

Author: bors

Cargo.toml

@@ -99,6 +99,7 @@ features = [
 [dev-dependencies]
 cargo-test-macro = { path = "crates/cargo-test-macro" }
 cargo-test-support = { path = "crates/cargo-test-support" }
+same-file = "1.0.6"
 snapbox = { version = "0.3.0", features = ["diff", "path"] }
 
 [build-dependencies]

src/cargo/core/compiler/mod.rs

@@ -305,6 +305,19 @@ fn rustc(cx: &mut Context<'_, '_>, unit: &Unit, exec: &Arc<dyn Executor>) -> Car
                     paths::remove_file(&dst)?;
                 }
             }
+
+            // Some linkers do not remove the executable, but truncate and modify it.
+            // That results in the old hard-link being modified even after renamed.
+            // We delete the old artifact here to prevent this behavior from confusing users.
+            // See rust-lang/cargo#8348.
+            if output.hardlink.is_some() && output.path.exists() {
+                _ = paths::remove_file(&output.path).map_err(|e| {
+                    log::debug!(
+                        "failed to delete previous output file `{:?}`: {e:?}",
+                        output.path
+                    );
+                });
+            }
         }
 
         fn verbose_if_simple_exit_code(err: Error) -> Error {

tests/testsuite/build.rs

@@ -6247,3 +6247,32 @@ fn primary_package_env_var() {
 
     foo.cargo("test").run();
 }
+
+#[cargo_test]
+fn renamed_uplifted_artifact_remains_unmodified_after_rebuild() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                authors = []
+                version = "0.0.0"
+            "#,
+        )
+        .file("src/main.rs", "fn main() {}")
+        .build();
+
+    p.cargo("build").run();
+
+    let bin = p.bin("foo");
+    let renamed_bin = p.bin("foo-renamed");
+
+    fs::rename(&bin, &renamed_bin).unwrap();
+
+    p.change_file("src/main.rs", "fn main() { eprintln!(\"hello, world\"); }");
+    p.cargo("build").run();
+
+    let not_the_same = !same_file::is_same_file(bin, renamed_bin).unwrap();
+    assert!(not_the_same, "renamed uplifted artifact must be unmodified");
+}