fix(watcher): filter Remove events by path to prevent false removed reports (closes #15)

crates/core/src/watcher/file_watcher.rs

@@ -35,6 +35,43 @@ struct WatchState {
     last_inode: u64,
 }
 
+fn process_event(event: Event, watch_path: &Path, state: &mut WatchState) -> Option<FileEvent> {
+    if !event.paths.iter().any(|p| p == watch_path) {
+        return None;
+    }
+
+    match event.kind {
+        EventKind::Modify(_) | EventKind::Create(_) | EventKind::Any => {}
+        EventKind::Remove(_) => return Some(FileEvent::Removed),
+        _ => return None,
+    }
+
+    let current_inode = get_inode(watch_path).unwrap_or(0);
+    let current_size = std::fs::metadata(watch_path).map(|m| m.len()).unwrap_or(0);
+
+    if current_inode != 0 && state.last_inode != 0 && current_inode != state.last_inode {
+        state.last_inode = current_inode;
+        state.last_size = current_size;
+        Some(FileEvent::Rotated {
+            new_inode: current_inode,
+        })
+    } else if current_size > state.last_size {
+        state.last_size = current_size;
+        state.last_inode = current_inode;
+        Some(FileEvent::Appended {
+            new_size: current_size,
+        })
+    } else if current_size < state.last_size {
+        state.last_size = current_size;
+        state.last_inode = current_inode;
+        Some(FileEvent::Truncated {
+            new_size: current_size,
+        })
+    } else {
+        None
+    }
+}
+
 // ─── FileWatcher ────────────────────────────────────────────────────────────
 pub struct FileWatcher {
     rx: Receiver<FileEvent>,
@@ -65,47 +102,14 @@ impl FileWatcher {
                     }
                 };
 
-                match event.kind {
-                    EventKind::Modify(_) | EventKind::Create(_) | EventKind::Any => {}
-                    EventKind::Remove(_) => {
-                        let _ = tx.try_send(FileEvent::Removed);
-                        return;
-                    }
-                    _ => return,
-                }
-
-                if !event.paths.iter().any(|p| p == &watch_path) {
-                    return;
-                }
-
-                let current_inode = get_inode(&watch_path).unwrap_or(0);
-                let current_size = std::fs::metadata(&watch_path).map(|m| m.len()).unwrap_or(0);
-
                 let mut st = state.lock().unwrap_or_else(|poison| {
                     // Recover from poisoned mutex — state only tracks last_size
                     // and last_inode for event dedup. Stale values at worst
                     // cause a duplicate event, which is harmless.
                     poison.into_inner()
                 });
-
-                if current_inode != 0 && st.last_inode != 0 && current_inode != st.last_inode {
-                    let _ = tx.try_send(FileEvent::Rotated {
-                        new_inode: current_inode,
-                    });
-                    st.last_inode = current_inode;
-                    st.last_size = current_size;
-                } else if current_size > st.last_size {
-                    let _ = tx.try_send(FileEvent::Appended {
-                        new_size: current_size,
-                    });
-                    st.last_size = current_size;
-                    st.last_inode = current_inode;
-                } else if current_size < st.last_size {
-                    let _ = tx.try_send(FileEvent::Truncated {
-                        new_size: current_size,
-                    });
-                    st.last_size = current_size;
-                    st.last_inode = current_inode;
+                if let Some(fe) = process_event(event, &watch_path, &mut st) {
+                    let _ = tx.try_send(fe);
                 }
             })?;
 
@@ -150,6 +154,56 @@ mod tests {
         events
     }
 
+    #[test]
+    fn test_remove_wrong_path_ignored() {
+        let dir = tempfile::tempdir().expect("create temp dir");
+        let watched = dir.path().join("watched.log");
+        let other = dir.path().join("other.log");
+        std::fs::write(&watched, b"hello\n").expect("write watched");
+        std::fs::write(&other, b"other\n").expect("write other");
+
+        let mut state = WatchState {
+            last_size: 6,
+            last_inode: get_inode(&watched).unwrap_or(0),
+        };
+
+        let event = Event {
+            kind: EventKind::Remove(notify::event::RemoveKind::File),
+            paths: vec![other.clone()],
+            attrs: Default::default(),
+        };
+
+        let result = process_event(event, &watched, &mut state);
+        assert_eq!(
+            result, None,
+            "Remove for non-watched path should be ignored"
+        );
+    }
+
+    #[test]
+    fn test_remove_correct_path_emits_removed() {
+        let dir = tempfile::tempdir().expect("create temp dir");
+        let watched = dir.path().join("watched.log");
+        std::fs::write(&watched, b"hello\n").expect("write watched");
+
+        let mut state = WatchState {
+            last_size: 6,
+            last_inode: get_inode(&watched).unwrap_or(0),
+        };
+
+        let event = Event {
+            kind: EventKind::Remove(notify::event::RemoveKind::File),
+            paths: vec![watched.clone()],
+            attrs: Default::default(),
+        };
+
+        let result = process_event(event, &watched, &mut state);
+        assert!(
+            matches!(result, Some(FileEvent::Removed)),
+            "Remove for watched path should emit Removed"
+        );
+    }
+
     #[test]
     fn test_watcher_append() {
         let dir = tempfile::tempdir().expect("create temp dir");
@@ -253,4 +307,4 @@ mod tests {
             }
         );
     }
-}
+}