Extract extension_directories transforms from Zod schema

Move removeTrailingPathSeparator and fixSingleWildcards out of
ExtensionDirectoriesSchema so parsed config preserves the raw TOML
value. Consumers (loader, file-watcher) now call the explicit
normalizeExtensionDirectories() helper at point of use.

Phase 2 of the config model cleanup — extension_directories is a
CLI-only field with no write-path or API impact.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ryancbahan

packages/app/src/cli/models/app/app.test.ts

@@ -10,6 +10,7 @@ import {
   getUIExtensionRendererVersion,
   isCurrentAppSchema,
   isLegacyAppSchema,
+  normalizeExtensionDirectories,
   validateExtensionsHandlesInCollection,
   validateFunctionExtensionsWithUiHandle,
 } from './app.js'
@@ -99,32 +100,37 @@ describe('app schema validation', () => {
       expect(isCurrentAppSchema(config)).toBe(false)
     })
 
-    test('extension_directories should be transformed to double asterisks', () => {
+    test('extension_directories preserves raw values without transformation', () => {
       const config = {
         ...CORRECT_CURRENT_APP_SCHEMA,
         extension_directories: ['extensions/*'],
       }
       const parsed = AppSchema.parse(config)
-      expect(parsed.extension_directories).toEqual(['extensions/**'])
+      expect(parsed.extension_directories).toEqual(['extensions/*'])
     })
+  })
+})
 
-    test('extension_directories is not transformed if it ends with double asterisks', () => {
-      const config = {
-        ...CORRECT_CURRENT_APP_SCHEMA,
-        extension_directories: ['extensions/**'],
-      }
-      const parsed = AppSchema.parse(config)
-      expect(parsed.extension_directories).toEqual(['extensions/**'])
-    })
+describe('normalizeExtensionDirectories', () => {
+  test('converts single trailing wildcard to double asterisks', () => {
+    expect(normalizeExtensionDirectories(['extensions/*'])).toEqual(['extensions/**'])
+  })
 
-    test('extension_directories is not transformed if it doesnt end with a wildcard', () => {
-      const config = {
-        ...CORRECT_CURRENT_APP_SCHEMA,
-        extension_directories: ['extensions'],
-      }
-      const parsed = AppSchema.parse(config)
-      expect(parsed.extension_directories).toEqual(['extensions'])
-    })
+  test('preserves double asterisks', () => {
+    expect(normalizeExtensionDirectories(['extensions/**'])).toEqual(['extensions/**'])
+  })
+
+  test('does not transform paths without wildcards', () => {
+    expect(normalizeExtensionDirectories(['extensions'])).toEqual(['extensions'])
+  })
+
+  test('strips trailing path separators before fixing wildcards', () => {
+    expect(normalizeExtensionDirectories(['extensions/'])).toEqual(['extensions'])
+    expect(normalizeExtensionDirectories(['extensions\\'])).toEqual(['extensions'])
+  })
+
+  test('returns undefined for undefined input', () => {
+    expect(normalizeExtensionDirectories(undefined)).toBeUndefined()
   })
 })
 

packages/app/src/cli/models/app/app.ts

@@ -34,11 +34,7 @@ import {deepMergeObjects} from '@shopify/cli-kit/common/object'
 
 // Schemas for loading app configuration
 
-const ExtensionDirectoriesSchema = zod
-  .array(zod.string())
-  .optional()
-  .transform(removeTrailingPathSeparator)
-  .transform(fixSingleWildcards)
+const ExtensionDirectoriesSchema = zod.array(zod.string()).optional()
 
 /**
  * Schema for a freshly minted app template.
@@ -74,6 +70,14 @@ function fixSingleWildcards(value: string[] | undefined) {
   return value?.map((dir) => dir.replace(/([^\*])\*$/, '$1**'))
 }
 
+/**
+ * Normalize extension directories for glob/chokidar consumption:
+ * strips trailing path separators, then converts single trailing `*` to `**`.
+ */
+export function normalizeExtensionDirectories(dirs: string[] | undefined): string[] | undefined {
+  return fixSingleWildcards(removeTrailingPathSeparator(dirs))
+}
+
 /**
  * Schema for loading template config during app init.
  * Uses passthrough() to allow any extra keys from full-featured templates

packages/app/src/cli/models/app/loader.ts

@@ -20,6 +20,7 @@ import {
   isLegacyAppSchema,
   TemplateConfigSchema,
   getTemplateScopesArray,
+  normalizeExtensionDirectories,
 } from './app.js'
 import {parseHumanReadableError} from './error-parsing.js'
 import {configurationFileNames, dotEnvFileNames} from '../../constants.js'
@@ -630,7 +631,8 @@ class AppLoader<TConfig extends AppConfiguration, TModuleSpec extends ExtensionS
   }
 
   private async createExtensionInstances(appDirectory: string, extensionDirectories?: string[]) {
-    const extensionConfigPaths = [...(extensionDirectories ?? [defaultExtensionDirectory])].map((extensionPath) => {
+    const normalizedDirs = normalizeExtensionDirectories(extensionDirectories)
+    const extensionConfigPaths = [...(normalizedDirs ?? [defaultExtensionDirectory])].map((extensionPath) => {
       return joinPath(appDirectory, extensionPath, '*.extension.toml')
     })
     extensionConfigPaths.push(`!${joinPath(appDirectory, '**/node_modules/**')}`)

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

@@ -1,5 +1,5 @@
 /* eslint-disable no-case-declarations */
-import {AppLinkedInterface} from '../../../models/app/app.js'
+import {AppLinkedInterface, normalizeExtensionDirectories} from '../../../models/app/app.js'
 import {configurationFileNames} from '../../../constants.js'
 import {dirname, joinPath, normalizePath, relativePath} from '@shopify/cli-kit/node/path'
 import {FSWatcher} from 'chokidar'
@@ -85,7 +85,9 @@ export class FileWatcher {
    * This ensures the watcher picks up any changes in what files need to be watched.
    */
   async start(): Promise<void> {
-    const extensionDirectories = [...(this.app.configuration.extension_directories ?? ['extensions'])]
+    const extensionDirectories = [
+      ...(normalizeExtensionDirectories(this.app.configuration.extension_directories) ?? ['extensions']),
+    ]
     const fullExtensionDirectories = extensionDirectories.map((directory) => joinPath(this.app.directory, directory))
     const watchPaths = [this.app.configPath, ...fullExtensionDirectories]