CLI: Fix CSF factories addon syncing in storybook add command

code/core/src/common/utils/load-main-config.ts

@@ -14,16 +14,18 @@ import { validateConfigurationFiles } from './validate-configuration-files';
 export async function loadMainConfig({
   configDir = '.storybook',
   cwd,
+  skipCache,
 }: {
   configDir: string;
   cwd?: string;
+  skipCache?: boolean;
 }): Promise<StorybookConfig> {
   await validateConfigurationFiles(configDir, cwd);
 
   const mainPath = getInterpretedFile(resolve(configDir, 'main')) as string;
 
   try {
-    const out = await importModule(mainPath);
+    const out = await importModule(mainPath, { skipCache });
     return out;
   } catch (e) {
     if (!(e instanceof Error)) {

code/core/src/shared/utils/module.ts

@@ -51,7 +51,10 @@ let isTypescriptLoaderRegistered = false;
  * // Returns the default export or the entire module
  * ```
  */
-export async function importModule(path: string) {
+export async function importModule(
+  path: string,
+  { skipCache = false }: { skipCache?: boolean } = {}
+) {
   if (!isTypescriptLoaderRegistered) {
     const typescriptLoaderUrl = importMetaResolve('storybook/internal/bin/loader');
     register(typescriptLoaderUrl, import.meta.url);
@@ -61,12 +64,17 @@ export async function importModule(path: string) {
   let mod;
   try {
     const resolvedPath = win32.isAbsolute(path) ? pathToFileURL(path).href : path;
-    mod = await import(resolvedPath);
+    // When applicable, add a hash to the import URL to bypass cache
+    const importUrl = skipCache ? `${resolvedPath}?${Date.now()}` : resolvedPath;
+    mod = await import(importUrl);
   } catch (importError) {
     try {
       // fallback to require to support older behavior
       // this is relevant for presets that are only available with the "require" condition in a package's export map
       const require = createRequire(import.meta.url);
+      if (skipCache) {
+        delete require.cache[require.resolve(path)];
+      }
       mod = require(path);
     } catch (requireError) {
       /*

code/lib/cli-storybook/src/add.ts

@@ -1,8 +1,6 @@
-import { isAbsolute, join } from 'node:path';
-
 import {
   type PackageManagerName,
-  serverRequire,
+  loadMainConfig,
   syncStorybookAddons,
   versions,
 } from 'storybook/internal/common';
@@ -182,7 +180,8 @@ export async function add(
 
   // TODO: remove try/catch once CSF factories is shipped, for now gracefully handle any error
   try {
-    await syncStorybookAddons(mainConfig, previewConfigPath!, configDir);
+    const newMainConfig = await loadMainConfig({ configDir, skipCache: true });
+    await syncStorybookAddons(newMainConfig, previewConfigPath!, configDir);
   } catch (e) {
     //
   }