Add comment explaining why cc does not rebuild on env PATH change (#1247)

NobodyXu · web-flow · commit e53eba374f9e · 2024-10-19T19:31:26.000+11:00
diff --git a/src/lib.rs b/src/lib.rs
@@ -3736,6 +3736,8 @@ impl Build {
         if let Some(val) = self.env_cache.read().unwrap().get(v).cloned() {
             return val;
         }
+        // Excluding `PATH` prevents spurious rebuilds on Windows, see
+        // <https://github.com/rust-lang/cc-rs/pull/1215> for details.
         if self.emit_rerun_if_env_changed && !provided_by_cargo(v) && v != "PATH" {
             self.cargo_output
                 .print_metadata(&format_args!("cargo:rerun-if-env-changed={}", v));

Original file line number	Diff line number	Diff line change
`@@ -3736,6 +3736,8 @@ impl Build {`
`3736`	`3736`	`if let Some(val) = self.env_cache.read().unwrap().get(v).cloned() {`
`3737`	`3737`	`return val;`
`3738`	`3738`	`}`
	`3739`	+ // Excluding `PATH` prevents spurious rebuilds on Windows, see
	`3740`	`+ // <https://github.com/rust-lang/cc-rs/pull/1215> for details.`
`3739`	`3741`	`if self.emit_rerun_if_env_changed && !provided_by_cargo(v) && v != "PATH" {`
`3740`	`3742`	`self.cargo_output`
`3741`	`3743`	`.print_metadata(&format_args!("cargo:rerun-if-env-changed={}", v));`