Normalize macOS notify paths for watch matching

Author: pasunboneleve

CHANGELOG.md

@@ -5,6 +5,9 @@ All notable changes to `devloop` will be recorded in this file.
 ## [Unreleased]
 
 ### Fixed
+- Accepted macOS `notify` event paths reported under `/private/...`
+  for watched roots configured under `/var/...`, so file changes in
+  temp directories are no longer dropped by the watch classifier.
 - Made the CI smoke test wait for file watching to start before editing
   the watched fixture file, and retry the watched write until the state
   change is observed, avoiding startup races on macOS runners.

src/engine.rs

@@ -409,7 +409,7 @@ fn classify_events(
             continue;
         }
         for path in &event.paths {
-            let Ok(relative) = path.strip_prefix(root) else {
+            let Some(relative) = relativize_event_path(root, path) else {
                 continue;
             };
             for group in watch_groups {
@@ -428,6 +428,17 @@ fn classify_events(
         .collect()
 }
 
+fn relativize_event_path<'a>(root: &'a Path, path: &'a Path) -> Option<&'a Path> {
+    path.strip_prefix(root)
+        .ok()
+        .or_else(|| strip_private_prefix_variant(root, path))
+}
+
+fn strip_private_prefix_variant<'a>(root: &'a Path, path: &'a Path) -> Option<&'a Path> {
+    let private_root = Path::new("/private").join(root.strip_prefix("/").ok()?);
+    path.strip_prefix(&private_root).ok()
+}
+
 fn normalize_path(path: &Path) -> String {
     path.components()
         .map(|component| component.as_os_str().to_string_lossy())
@@ -484,6 +495,24 @@ mod tests {
         assert_eq!(grouped["content"], vec!["content/posts/example.md"]);
     }
 
+    #[test]
+    fn classify_changes_by_workflow_accepts_private_var_event_paths() {
+        let root = PathBuf::from("/var/folders/example/tmp");
+        let groups =
+            vec![CompiledWatchGroup::for_test(&["watched.txt"], "content").expect("watch group")];
+        let events = vec![Event {
+            kind: EventKind::Modify(ModifyKind::Any),
+            paths: vec![PathBuf::from(
+                "/private/var/folders/example/tmp/watched.txt",
+            )],
+            attrs: Default::default(),
+        }];
+
+        let grouped = classify_events(&root, &groups, &events);
+
+        assert_eq!(grouped["content"], vec!["watched.txt"]);
+    }
+
     #[tokio::test]
     async fn write_state_step_renders_session_template() {
         let state_path = unique_state_path();