Watch asset directories for changes during dev

packages/app/src/cli/models/extensions/extension-instance.test.ts

@@ -717,6 +717,81 @@ describe('watchedFiles', async () => {
       vi.mocked(extractImportPathsRecursively).mockReset()
     })
   })
+
+  test('includes additional watched paths registered via addWatchedPath', async () => {
+    await inTemporaryDirectory(async (tmpDir) => {
+      const extensionInstance = await testUIExtension({
+        directory: tmpDir,
+        entrySourceFilePath: joinPath(tmpDir, 'src', 'index.ts'),
+      })
+
+      const srcDir = joinPath(tmpDir, 'src')
+      await mkdir(srcDir)
+      await writeFile(joinPath(srcDir, 'index.ts'), 'code')
+
+      vi.mocked(extractImportPathsRecursively).mockImplementation((filePath) => [filePath])
+
+      const assetsDir = joinPath(tmpDir, 'assets')
+      await mkdir(assetsDir)
+      extensionInstance.addWatchedPath(assetsDir)
+
+      const watchedFiles = extensionInstance.watchedFiles()
+
+      expect(watchedFiles).toContain(assetsDir)
+
+      vi.mocked(extractImportPathsRecursively).mockReset()
+    })
+  })
+
+  test('clearWatchedPaths removes all registered paths', async () => {
+    await inTemporaryDirectory(async (tmpDir) => {
+      const extensionInstance = await testUIExtension({
+        directory: tmpDir,
+        entrySourceFilePath: joinPath(tmpDir, 'src', 'index.ts'),
+      })
+
+      const srcDir = joinPath(tmpDir, 'src')
+      await mkdir(srcDir)
+      await writeFile(joinPath(srcDir, 'index.ts'), 'code')
+
+      vi.mocked(extractImportPathsRecursively).mockImplementation((filePath) => [filePath])
+
+      extensionInstance.addWatchedPath(joinPath(tmpDir, 'assets'))
+      extensionInstance.clearWatchedPaths()
+
+      const watchedFiles = extensionInstance.watchedFiles()
+
+      expect(watchedFiles).not.toContain(joinPath(tmpDir, 'assets'))
+
+      vi.mocked(extractImportPathsRecursively).mockReset()
+    })
+  })
+
+  test('getWatchedPaths returns registered paths', async () => {
+    await inTemporaryDirectory(async (tmpDir) => {
+      const extensionInstance = await testUIExtension({directory: tmpDir})
+
+      const assetsDir = joinPath(tmpDir, 'assets')
+      extensionInstance.addWatchedPath(assetsDir)
+
+      const paths = extensionInstance.getWatchedPaths()
+
+      expect(paths.has(assetsDir)).toBe(true)
+      expect(paths.size).toBe(1)
+    })
+  })
+
+  test('addWatchedPath deduplicates identical paths', async () => {
+    await inTemporaryDirectory(async (tmpDir) => {
+      const extensionInstance = await testUIExtension({directory: tmpDir})
+
+      const assetsDir = joinPath(tmpDir, 'assets')
+      extensionInstance.addWatchedPath(assetsDir)
+      extensionInstance.addWatchedPath(assetsDir)
+
+      expect(extensionInstance.getWatchedPaths().size).toBe(1)
+    })
+  })
 })
 
 describe('rescanImports', async () => {

packages/app/src/cli/models/extensions/extension-instance.ts

@@ -51,6 +51,7 @@ export class ExtensionInstance<TConfiguration extends BaseConfigType = BaseConfi
   specification: ExtensionSpecification
   uid: string
   private cachedImportPaths?: string[]
+  private readonly additionalWatchedPaths = new Set<string>()
 
   get graphQLType() {
     return (this.specification.graphQLType ?? this.specification.identifier).toUpperCase()
@@ -460,9 +461,23 @@ export class ExtensionInstance<TConfiguration extends BaseConfigType = BaseConfi
       watchedFiles.push(...importedFiles)
     }
 
+    watchedFiles.push(...this.additionalWatchedPaths)
+
     return [...new Set(watchedFiles.map((file) => normalizePath(file)))]
   }
 
+  addWatchedPath(absolutePath: string): void {
+    this.additionalWatchedPaths.add(normalizePath(absolutePath))
+  }
+
+  getWatchedPaths(): ReadonlySet<string> {
+    return this.additionalWatchedPaths
+  }
+
+  clearWatchedPaths(): void {
+    this.additionalWatchedPaths.clear()
+  }
+
   /**
    * Rescans imports for this extension and updates the cached import paths
    * Returns true if the imports changed

packages/app/src/cli/services/build/steps/include-assets-step.test.ts

@@ -18,7 +18,8 @@ describe('executeIncludeAssetsStep', () => {
     mockExtension = {
       directory: '/test/extension',
       outputPath: '/test/output/extension.js',
-    } as ExtensionInstance
+      addWatchedPath: vi.fn(),
+    } as unknown as ExtensionInstance
 
     mockContext = {
       extension: mockExtension,
@@ -232,6 +233,72 @@ describe('executeIncludeAssetsStep', () => {
       expect(result.filesCopied).toBe(2)
     })
 
+    test('registers directory source paths as watched paths on the extension', async () => {
+      // Given
+      const addWatchedPath = vi.fn()
+      const contextWithConfig = {
+        ...mockContext,
+        extension: {
+          ...mockExtension,
+          configuration: {static_root: 'public'},
+          addWatchedPath,
+        } as unknown as ExtensionInstance,
+      }
+
+      vi.mocked(fs.fileExists).mockResolvedValue(true)
+      vi.mocked(fs.isDirectory).mockResolvedValue(true)
+      vi.mocked(fs.copyDirectoryContents).mockResolvedValue()
+      vi.mocked(fs.glob).mockResolvedValue(['index.html', 'logo.png'])
+
+      const step: LifecycleStep = {
+        id: 'copy-static',
+        name: 'Copy Static',
+        type: 'include_assets',
+        config: {
+          inclusions: [{type: 'configKey', key: 'static_root'}],
+        },
+      }
+
+      // When
+      await executeIncludeAssetsStep(step, contextWithConfig)
+
+      // Then — directory source is registered as a watched path
+      expect(addWatchedPath).toHaveBeenCalledWith('/test/extension/public')
+    })
+
+    test('does not register file source paths as watched paths', async () => {
+      // Given
+      const addWatchedPath = vi.fn()
+      const contextWithConfig = {
+        ...mockContext,
+        extension: {
+          ...mockExtension,
+          configuration: {schema_path: 'src/schema.json'},
+          addWatchedPath,
+        } as unknown as ExtensionInstance,
+      }
+
+      vi.mocked(fs.fileExists).mockResolvedValue(true)
+      vi.mocked(fs.isDirectory).mockResolvedValue(false)
+      vi.mocked(fs.copyFile).mockResolvedValue()
+      vi.mocked(fs.mkdir).mockResolvedValue()
+
+      const step: LifecycleStep = {
+        id: 'copy-schema',
+        name: 'Copy Schema',
+        type: 'include_assets',
+        config: {
+          inclusions: [{type: 'configKey', key: 'schema_path'}],
+        },
+      }
+
+      // When
+      await executeIncludeAssetsStep(step, contextWithConfig)
+
+      // Then — file sources are not registered as watched paths
+      expect(addWatchedPath).not.toHaveBeenCalled()
+    })
+
     test('skips silently when configKey is absent from config', async () => {
       // Given — configuration has no static_root
       const contextWithoutConfig = {

packages/app/src/cli/services/build/steps/include-assets-step.ts

@@ -151,7 +151,12 @@ export async function executeIncludeAssetsStep(
       usedBasenames,
       preserveFilePaths: entry.preserveFilePaths,
     })
-    result.pathMap.forEach((val, key) => aggregatedPathMap.set(key, val))
+    result.pathMap.forEach((val, key) => {
+      aggregatedPathMap.set(key, val)
+      if (Array.isArray(val)) {
+        extension.addWatchedPath(joinPath(extension.directory, key))
+      }
+    })
     configKeyCount += result.filesCopied
   }
 

packages/app/src/cli/services/dev/app-events/app-event-watcher.ts

@@ -139,7 +139,13 @@ export class AppEventWatcher extends EventEmitter {
           const buildableEvents = appEvent.extensionEvents.filter((extEvent) => extEvent.type !== EventType.Deleted)
 
           // Build the created/updated extensions and update the extension events with the build result
+          const watchedPathsBefore = new Set(buildableEvents.flatMap((ev) => [...ev.extension.getWatchedPaths()]))
           await this.buildExtensions(buildableEvents)
+          const watchedPathsAfter = new Set(buildableEvents.flatMap((ev) => [...ev.extension.getWatchedPaths()]))
+          const watchedPathsChanged =
+            watchedPathsBefore.size !== watchedPathsAfter.size ||
+            [...watchedPathsAfter].some((watchedPath) => !watchedPathsBefore.has(watchedPath))
+          if (watchedPathsChanged) await this.fileWatcher?.start()
 
           // Generate the extension types after building the extensions so new imports are included
           // Skip if the app was reloaded, as generateExtensionTypes was already called during reload

packages/app/src/cli/services/dev/app-events/file-watcher.test.ts

@@ -810,6 +810,100 @@ describe('file-watcher events', () => {
     })
   })
 
+  describe('directory watched path handle resolution', () => {
+    test('resolves extension handle for files inside a watched directory', async () => {
+      // Given — extension with a watched directory (e.g., assets/)
+      const assetsDir = '/extensions/ui_extension_1/assets'
+      const ext = await testUIExtension({
+        type: 'ui_extension',
+        handle: 'my-ext',
+        directory: '/extensions/ui_extension_1',
+      })
+      // watchedFiles() returns individual files AND the directory path.
+      // shouldIgnoreEvent calls matchGlob against this list, so include
+      // a glob pattern for the directory so files inside it are not filtered out.
+      mockExtensionWatchedFiles(ext, ['/extensions/ui_extension_1/index.js', `${assetsDir}/**/*`, assetsDir])
+
+      const app = testAppLinked({
+        allExtensions: [ext],
+        directory: '/',
+        configPath: '/shopify.app.toml',
+        configuration: {
+          ...DEFAULT_CONFIG,
+          extension_directories: ['/extensions'],
+        } as any,
+      })
+
+      let eventHandler: any
+      const mockWatcher = {
+        on: vi.fn((event: string, listener: any) => {
+          if (event === 'all') eventHandler = listener
+          return mockWatcher
+        }),
+        close: vi.fn(() => Promise.resolve()),
+      }
+      vi.spyOn(chokidar, 'watch').mockReturnValue(mockWatcher as any)
+
+      const onChange = vi.fn()
+      const fileWatcher = new FileWatcher(app, outputOptions, 50)
+      fileWatcher.onChange(onChange)
+      await fileWatcher.start()
+
+      // When — a file inside the watched directory changes
+      await eventHandler('change', `${assetsDir}/logo.png`)
+      await sleep(0.15)
+
+      // Then — event is emitted with the correct extension handle
+      await vi.waitFor(
+        () => {
+          expect(onChange).toHaveBeenCalled()
+          const events = onChange.mock.calls.find((call) => call[0].length > 0)?.[0]
+          expect(events).toBeDefined()
+          expect(events[0].type).toBe('file_updated')
+          expect(events[0].extensionHandle).toBe('my-ext')
+        },
+        {timeout: 1000, interval: 50},
+      )
+    })
+
+    test('does not pass watched directories to chokidar', async () => {
+      // Given — extension with both files and a directory in watchedFiles
+      const ext = await testUIExtension({
+        type: 'ui_extension',
+        handle: 'my-ext',
+        directory: '/extensions/ui_extension_1',
+      })
+      mockExtensionWatchedFiles(ext, ['/extensions/ui_extension_1/index.js', '/extensions/ui_extension_1/assets'])
+
+      const app = testAppLinked({
+        allExtensions: [ext],
+        directory: '/',
+        configPath: '/shopify.app.toml',
+        configuration: {
+          ...DEFAULT_CONFIG,
+          extension_directories: ['/extensions'],
+        } as any,
+      })
+
+      let watchedPaths: string[] = []
+      vi.spyOn(chokidar, 'watch').mockImplementation((paths) => {
+        watchedPaths = paths as string[]
+        return {
+          on: vi.fn().mockReturnThis(),
+          close: vi.fn().mockResolvedValue(undefined),
+        } as any
+      })
+
+      // When
+      const fileWatcher = new FileWatcher(app, outputOptions)
+      await fileWatcher.start()
+
+      // Then — files are passed to chokidar but directories are not
+      expect(watchedPaths).toContain('/extensions/ui_extension_1/index.js')
+      expect(watchedPaths).not.toContain('/extensions/ui_extension_1/assets')
+    })
+  })
+
   describe('refreshWatchedFiles', () => {
     test('closes and recreates the watcher with updated paths', async () => {
       // Given
@@ -844,4 +938,67 @@ describe('file-watcher events', () => {
       expect(watchedPaths[1]).toEqual(watchedPaths[0])
     })
   })
+
+  describe('file deletion events', () => {
+    test('file_deleted event is emitted even when the file is already gone from disk', async () => {
+      // Given: an extension with a watched file
+      const ext = await testUIExtension({
+        type: 'ui_extension',
+        handle: 'del_ext',
+        directory: '/extensions/del_ext',
+      })
+      const filePath = '/extensions/del_ext/assets/image.png'
+      // Simulate real behavior: watchedFiles() returns the file at start,
+      // but after deletion it no longer appears in the glob results
+      let watchedFilesResult: string[] = [filePath]
+      vi.spyOn(ext, 'watchedFiles').mockImplementation(() => watchedFilesResult)
+
+      const testApp = testAppLinked({
+        allExtensions: [ext],
+        directory: '/',
+        configPath: '/shopify.app.toml',
+        configuration: {
+          ...DEFAULT_CONFIG,
+          extension_directories: ['/extensions'],
+        } as any,
+      })
+
+      let eventHandler: any
+      const mockWatcher = {
+        on: vi.fn((event: string, listener: any) => {
+          if (event === 'all') eventHandler = listener
+          return mockWatcher
+        }),
+        close: vi.fn().mockResolvedValue(undefined),
+      }
+      vi.spyOn(chokidar, 'watch').mockReturnValue(mockWatcher as any)
+      vi.mocked(fileExistsSync).mockReturnValue(false)
+
+      const fileWatcher = new FileWatcher(testApp, outputOptions, 50)
+      const onChange = vi.fn()
+      fileWatcher.onChange(onChange)
+      await fileWatcher.start()
+      await flushPromises()
+
+      // Simulate the file being deleted from disk — watchedFiles() no longer returns it
+      watchedFilesResult = []
+      await eventHandler('unlink', filePath, undefined)
+      await sleep(0.15)
+
+      // Then: the file_deleted event should still be emitted
+      await vi.waitFor(
+        () => {
+          expect(onChange).toHaveBeenCalled()
+          const calls = onChange.mock.calls
+          const actualEvents = calls.find((call) => call[0].length > 0)?.[0]
+          expect(actualEvents).toBeDefined()
+          expect(actualEvents).toHaveLength(1)
+          expect(actualEvents[0].type).toBe('file_deleted')
+          expect(actualEvents[0].path).toBe(normalizePath(filePath))
+          expect(actualEvents[0].extensionHandle).toBe('del_ext')
+        },
+        {timeout: 1000, interval: 50},
+      )
+    })
+  })
 })