Refactor change detection and enhance event handling in persistent indexing

- Improved the `emit_change_event` method in `DatabaseAdapter` to handle resource events more effectively, including detailed logging for event emissions.
- Updated the `PersistentEventHandler` to ensure paths are registered with the filesystem watcher upon startup, enhancing real-time monitoring capabilities.
- Introduced new event collectors for better diagnostics and logging of filesystem and core events during tests.
- Enhanced integration tests to cover various scenarios, including batch file operations and delete/restore patterns, ensuring accurate event handling and preventing duplicates.

core/src/ops/indexing/change_detection/persistent.rs

@@ -216,7 +216,8 @@ impl ChangeHandler for DatabaseAdapter {
 			state
 				.entry_id_cache
 				.insert(parent_path.to_path_buf(), parent_id);
-		} else if let Ok(Some(parent_id)) = DatabaseStorage::resolve_parent_id(&self.db, parent_path).await
+		} else if let Ok(Some(parent_id)) =
+			DatabaseStorage::resolve_parent_id(&self.db, parent_path).await
 		{
 			// Cache the parent ID for future lookups
 			state
@@ -586,8 +587,46 @@ impl ChangeHandler for DatabaseAdapter {
 
 	async fn emit_change_event(&self, entry: &EntryRef, change_type: ChangeType) -> Result<()> {
 		use crate::domain::ResourceManager;
+		use crate::infra::event::Event;
 
-		if let Some(uuid) = entry.uuid {
+		tracing::debug!(
+			"emit_change_event called: {:?} for {} (uuid: {:?})",
+			change_type,
+			entry.path.display(),
+			entry.uuid
+		);
+
+		let Some(uuid) = entry.uuid else {
+			tracing::warn!(
+				"Entry has no UUID, cannot emit {:?} event for {}",
+				change_type,
+				entry.path.display()
+			);
+			return Ok(());
+		};
+
+		match change_type {
+			ChangeType::Deleted => {
+				// Emit ResourceDeleted event so frontend can remove from cache
+				// Use "file" resource_type to match ephemeral events (frontend listens for "file")
+				tracing::debug!(
+					"Emitting ResourceDeleted for persistent delete: {} (id: {})",
+					entry.path.display(),
+					uuid
+				);
+				self.context.events.emit(Event::ResourceDeleted {
+					resource_type: "file".to_string(),
+					resource_id: uuid,
+				});
+			}
+			ChangeType::Created | ChangeType::Modified | ChangeType::Moved => {
+				// Emit ResourceChanged event for UI updates
+				tracing::debug!(
+					"Emitting ResourceChanged for persistent {:?}: {} (id: {})",
+					change_type,
+					entry.path.display(),
+					uuid
+				);
 				let resource_manager =
 					ResourceManager::new(Arc::new(self.db.clone()), self.context.events.clone());
 
@@ -596,10 +635,18 @@ impl ChangeHandler for DatabaseAdapter {
 					.await
 				{
 					tracing::warn!(
-					"Failed to emit resource event for {:?} entry: {}",
+						"Failed to emit resource event for {:?} entry {}: {}",
 						change_type,
+						entry.path.display(),
 						e
 					);
+				} else {
+					tracing::debug!(
+						"Successfully emitted ResourceChanged for {:?}: {}",
+						change_type,
+						entry.path.display()
+					);
+				}
 			}
 		}
 
@@ -728,12 +775,7 @@ impl<'a> IndexPersistence for DatabaseAdapterForJob<'a> {
 	) -> JobResult<()> {
 		use crate::ops::indexing::database_storage::DatabaseStorage;
 
-		DatabaseStorage::link_to_content_identity(
-			self.ctx.library_db(),
-			entry_id,
-			path,
-			cas_id,
-		)
+		DatabaseStorage::link_to_content_identity(self.ctx.library_db(), entry_id, path, cas_id)
 			.await
 			.map(|_| ())
 	}

core/src/ops/indexing/handlers/persistent.rs

@@ -124,18 +124,46 @@ impl PersistentEventHandler {
 		{
 			let mut locations = self.locations.write().await;
 			locations.insert(root_path.clone(), meta.clone());
+			debug!(
+				"Added location to map. Total locations: {}",
+				locations.len()
+			);
 		}
 
 		// Create worker if handler is running
 		if self.is_running.load(Ordering::SeqCst) {
+			debug!(
+				"Handler is running, creating worker for location {}",
+				location_id
+			);
 			self.ensure_worker(meta).await?;
+		} else {
+			debug!(
+				"Handler not running yet, worker will be created on start for location {}",
+				location_id
+			);
 		}
 
 		// Register path with FsWatcher if connected
 		if let Some(fs_watcher) = self.fs_watcher.read().await.as_ref() {
+			debug!(
+				"Registering path {} with FsWatcher (recursive)",
+				root_path.display()
+			);
 			fs_watcher
 				.watch_path(&root_path, sd_fs_watcher::WatchConfig::recursive())
 				.await?;
+			info!(
+				"Successfully registered {} with FsWatcher for location {}",
+				root_path.display(),
+				location_id
+			);
+		} else {
+			warn!(
+				"FsWatcher not connected, cannot watch path {} for location {}",
+				root_path.display(),
+				location_id
+			);
 		}
 
 		Ok(())
@@ -198,10 +226,35 @@ impl PersistentEventHandler {
 
 		debug!("Starting PersistentEventHandler");
 
-		// Create workers for all registered locations
+		// Create workers for all registered locations AND register paths with FsWatcher
+		// This is critical: locations may have been added before start() was called,
+		// when the FsWatcher wasn't connected yet, so we need to register them now.
 		let locations: Vec<LocationMeta> = self.locations.read().await.values().cloned().collect();
-		for meta in locations {
-			self.ensure_worker(meta).await?;
+		for meta in &locations {
+			self.ensure_worker(meta.clone()).await?;
+
+			// Register the path with the OS-level watcher (may have been skipped during add_location)
+			debug!(
+				"Registering path {} with FsWatcher for location {}",
+				meta.root_path.display(),
+				meta.id
+			);
+			if let Err(e) = fs_watcher
+				.watch_path(&meta.root_path, sd_fs_watcher::WatchConfig::recursive())
+				.await
+			{
+				error!(
+					"Failed to register path {} with FsWatcher: {}",
+					meta.root_path.display(),
+					e
+				);
+			} else {
+				info!(
+					"Successfully registered {} with FsWatcher for location {}",
+					meta.root_path.display(),
+					meta.id
+				);
+			}
 		}
 
 		// Start the event routing task
@@ -284,11 +337,24 @@ impl PersistentEventHandler {
 	) -> Result<()> {
 		let locs = locations.read().await;
 
+		trace!(
+			"Routing event {:?} for path: {} (checking {} locations)",
+			event.kind,
+			event.path.display(),
+			locs.len()
+		);
+
 		// Find the best matching location (longest prefix match)
 		let mut best_match: Option<&LocationMeta> = None;
 		let mut longest_len = 0;
 
 		for (root_path, meta) in locs.iter() {
+			trace!(
+				"  Checking location {} at {} for path {}",
+				meta.id,
+				root_path.display(),
+				event.path.display()
+			);
 			if event.path.starts_with(root_path) {
 				let len = root_path.as_os_str().len();
 				if len > longest_len {
@@ -299,10 +365,21 @@ impl PersistentEventHandler {
 		}
 
 		let Some(location) = best_match else {
-			trace!("Event not under any location: {}", event.path.display());
+			debug!(
+				"Event not under any location: {} (registered locations: {:?})",
+				event.path.display(),
+				locs.keys().collect::<Vec<_>>()
+			);
 			return Ok(());
 		};
 
+		debug!(
+			"Routing {:?} event for {} to location {}",
+			event.kind,
+			event.path.display(),
+			location.id
+		);
+
 		// Send to worker
 		let workers_map = workers.read().await;
 		if let Some(tx) = workers_map.get(&location.id) {
@@ -312,6 +389,12 @@ impl PersistentEventHandler {
 					location.id, e
 				);
 			}
+		} else {
+			warn!(
+				"No worker found for location {} (workers: {:?})",
+				location.id,
+				workers_map.keys().collect::<Vec<_>>()
+			);
 		}
 
 		Ok(())