refactor: improve namespace source update plugin lifecycle

packages/core/src/Source.ts

@@ -135,6 +135,7 @@ export default class Source {
   }
 
   async requestNamespaceSourceUpdate(
+    namespaceSourceDesc: string,
     updatedSourceFilesystem: IVolumeImmutable,
     sharedFilesystem: IVolumeImmutable,
     globalConfig: MutableData<unknown>
@@ -158,6 +159,9 @@ export default class Source {
       );
     }
     if (shouldInvokeAfterUpdate === true) {
+      console.log(
+        `[Mosaic][Source] namespace source ${namespaceSourceDesc} updated. Triggering 'afterNamespaceSourceUpdate for ${this.id.description}`
+      );
       this.filesystem.unfreeze();
       await this.invokeAfterUpdate(sharedFilesystem, globalConfig, 'afterNamespaceSourceUpdate');
       this.filesystem.freeze();

packages/core/src/SourceManager.ts

@@ -247,20 +247,21 @@ export default class SourceManager {
 
   #updateNamespaceSources(immutableSourceFilesystem: IVolumeImmutable, source: Source) {
     // Notify other frozen sources that share this sources namespace that something has changed.
+    const sourcesToUpdate = Array.from(this.#sources.values()).filter(
+      existingSource =>
+        existingSource !== source &&
+        existingSource.filesystem.frozen &&
+        existingSource.namespace === source.namespace
+    );
+
     return Promise.all(
-      Array.from(this.#sources.values()).map(existingSource => {
-        if (
-          existingSource !== source &&
-          existingSource.filesystem.frozen &&
-          existingSource.namespace === source.namespace
-        ) {
-          return existingSource.requestNamespaceSourceUpdate(
-            immutableSourceFilesystem,
-            this.#sharedFilesystem,
-            this.#globalConfig
-          );
-        }
-        return existingSource;
+      sourcesToUpdate.map(async sourceToUpdate => {
+        await sourceToUpdate.requestNamespaceSourceUpdate(
+          source.id.description,
+          immutableSourceFilesystem,
+          this.#sharedFilesystem,
+          this.#globalConfig
+        );
       })
     );
   }

packages/core/src/WorkerSubscription.ts

@@ -59,10 +59,12 @@ export default class WorkerSubscription {
     } else if (type === 'track') {
       this.#emitter.emit(EVENT.TRACK, { data: JSON.parse(textDecoder.decode(data)) });
     } else if (type === 'init') {
-      this.#emitter.emit(EVENT.START);
       if (data) {
-        // We receive a file buffer for 'init', not an object
-        this.#emitter.emit(EVENT.UPDATE, { data: JSON.parse(textDecoder.decode(data)) });
+        // We receive a file buffer (cached fs) for 'init', not an object
+        this.#emitter.emit(EVENT.START, { data: JSON.parse(textDecoder.decode(data)) });
+      } else {
+        // started with no cached fs
+        this.#emitter.emit(EVENT.START);
       }
     } else {
       this.#onError(

packages/plugins/src/BreadcrumbsPlugin.ts

@@ -123,8 +123,21 @@ const BreadcrumbsPlugin: PluginType<BreadcrumbsPluginPage, BreadcrumbsPluginOpti
       }
     }
   },
-  async shouldUpdateNamespaceSources() {
-    return true;
+  async shouldUpdateNamespaceSources(updatedSourceFilesystem, { ignorePages, namespace }) {
+    /**
+     * Only trigger an update when the updated source happens to be the "root" namespace source
+     * This is determined this by checking if the filesystem has files inside the "namespace" directory
+     *
+     * "child" sources will have the namespace directory but they wont have files until further down the directory hierarchy
+     */
+    const namespaceDirFiles = (await updatedSourceFilesystem.promises.glob(`${namespace}/*`, {
+      onlyFiles: true,
+      ignore: ignorePages.map(ignore => `**/${ignore}`),
+      cwd: '/'
+    })) as string[];
+
+    // the root namespace has updated
+    return namespaceDirFiles.length > 0;
   }
 };