refactor(core): use dynamic imports in client to avoid AsyncLocalStorage poisoning

Replace static imports of next/headers, next/navigation, and next-intl/server
with dynamic import() calls inside the hooks that use them. Static imports
cause these modules to be evaluated during module graph resolution when
next.config.ts imports this file, poisoning the process-wide AsyncLocalStorage
context. Dynamic imports defer module loading to call time, after Next.js has
fully initialized.

Author: matthewvolk

.changeset/dynamic-imports-client.md

@@ -0,0 +1,5 @@
+---
+"@bigcommerce/catalyst-core": minor
+---
+
+Use dynamic imports for next/headers, next/navigation, and next-intl/server in the client module to avoid AsyncLocalStorage poisoning during next.config.ts resolution

core/client/index.ts

@@ -1,22 +1,30 @@
 import { BigCommerceAuthError, createClient } from '@bigcommerce/catalyst-client';
-import { headers } from 'next/headers';
-// eslint-disable-next-line @typescript-eslint/no-restricted-imports
-import { redirect } from 'next/navigation';
-import { getLocale as getServerLocale } from 'next-intl/server';
 
 import { getChannelIdFromLocale } from '../channels.config';
 import { backendUserAgent } from '../user-agent';
 
+// next/headers, next/navigation, and next-intl/server are imported dynamically
+// (via `import()`) rather than statically. Static imports cause these modules to
+// be evaluated during module graph resolution when next.config.ts imports this
+// file, which poisons the process-wide AsyncLocalStorage context (pnpm symlinks
+// create two separate singleton instances of next/headers). Dynamic imports
+// defer module loading to call time, after Next.js has fully initialized.
+//
+// During config resolution, the dynamic import of next-intl/server succeeds but
+// getLocale() throws ("not supported in Client Components") — the try/catch
+// below absorbs this gracefully, and getChannelId falls back to defaultChannelId.
+
 const getLocale = async () => {
   try {
-    const locale = await getServerLocale();
+    const { getLocale: getServerLocale } = await import('next-intl/server');
 
-    return locale;
+    return await getServerLocale();
   } catch {
     /**
      * Next-intl `getLocale` only works on the server, and when middleware has run.
      *
      * Instances when `getLocale` will not work:
+     * - Requests during next.config.ts resolution
      * - Requests in middlewares
      * - Requests in `generateStaticParams`
      * - Request in api routes
@@ -45,6 +53,7 @@ export const client = createClient({
     const locale = await getLocale();
 
     if (fetchOptions?.cache && ['no-store', 'no-cache'].includes(fetchOptions.cache)) {
+      const { headers } = await import('next/headers');
       const ipAddress = (await headers()).get('X-Forwarded-For');
 
       if (ipAddress) {
@@ -61,8 +70,10 @@ export const client = createClient({
       headers: requestHeaders,
     };
   },
-  onError: (error, queryType) => {
+  onError: async (error, queryType) => {
     if (error instanceof BigCommerceAuthError && queryType === 'query') {
+      const { redirect } = await import('next/navigation');
+
       redirect('/api/auth/signout');
     }
   },