fix: Dynamic Usage Error when using previewData with generateStaticPa…

…rams and appDir (#43395)

fixes #43392 

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## Bug

- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [] Related issues linked using `fixes #number`
- []
[e2e](https://github.com/vercel/next.js/blob/canary/contributing/core/testing.md#writing-tests-for-nextjs)
tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see
[`contributing.md`](https://github.com/vercel/next.js/blob/canary/contributing.md)

## Documentation / Examples

- [x] Make sure the linting passes by running `pnpm build && pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)

Co-authored-by: JJ Kasper <jj@jjsweb.site>

packages/next/client/components/headers.ts

@@ -16,10 +16,6 @@ export function headers() {
 }
 
 export function previewData() {
-  if (staticGenerationBailout('previewData')) {
-    return {}
-  }
-
   const requestStore =
     requestAsyncStorage && 'getStore' in requestAsyncStorage
       ? requestAsyncStorage.getStore()!

test/e2e/app-dir/app-static.test.ts

@@ -66,6 +66,13 @@ describe('app-dir static/dynamic handling', () => {
         'hooks/use-pathname/slug.html',
         'hooks/use-pathname/slug.rsc',
         'hooks/use-search-params/[slug]/page.js',
+        'ssg-preview.html',
+        'ssg-preview.rsc',
+        'ssg-preview/[[...route]]/page.js',
+        'ssg-preview/test-2.html',
+        'ssg-preview/test-2.rsc',
+        'ssg-preview/test.html',
+        'ssg-preview/test.rsc',
         'ssr-auto/cache-no-store/page.js',
         'ssr-auto/fetch-revalidate-zero/page.js',
         'ssr-forced/page.js',
@@ -145,6 +152,21 @@ describe('app-dir static/dynamic handling', () => {
           initialRevalidateSeconds: false,
           srcRoute: '/force-static/[slug]',
         },
+        '/ssg-preview': {
+          dataRoute: '/ssg-preview.rsc',
+          initialRevalidateSeconds: false,
+          srcRoute: '/ssg-preview/[[...route]]',
+        },
+        '/ssg-preview/test': {
+          dataRoute: '/ssg-preview/test.rsc',
+          initialRevalidateSeconds: false,
+          srcRoute: '/ssg-preview/[[...route]]',
+        },
+        '/ssg-preview/test-2': {
+          dataRoute: '/ssg-preview/test-2.rsc',
+          initialRevalidateSeconds: false,
+          srcRoute: '/ssg-preview/[[...route]]',
+        },
       })
       expect(manifest.dynamicRoutes).toEqual({
         '/blog/[author]/[slug]': {
@@ -171,10 +193,26 @@ describe('app-dir static/dynamic handling', () => {
           fallback: null,
           routeRegex: '^\\/force\\-static\\/([^\\/]+?)(?:\\/)?$',
         },
+        '/ssg-preview/[[...route]]': {
+          dataRoute: '/ssg-preview/[[...route]].rsc',
+          dataRouteRegex: '^\\/ssg\\-preview(?:\\/(.+?))?\\.rsc$',
+          fallback: null,
+          routeRegex: '^\\/ssg\\-preview(?:\\/(.+?))?(?:\\/)?$',
+        },
       })
     })
   }
 
+  it('Should not throw Dynamic Server Usage error when using generateStaticParams with previewData', async () => {
+    const browserOnIndexPage = await webdriver(next.url, '/ssg-preview')
+
+    const content = await browserOnIndexPage
+      .elementByCss('#preview-data')
+      .text()
+
+    expect(content).toContain('previewData')
+  })
+
   it('should force SSR correctly for headers usage', async () => {
     const res = await fetchViaHTTP(next.url, '/force-static', undefined, {
       headers: {

test/e2e/app-dir/app-static/app/ssg-preview/[[...route]]/page.js

@@ -0,0 +1,29 @@
+import { previewData } from 'next/headers'
+
+export default function Page() {
+  const previewDataResult = previewData()
+
+  return (
+    <main>
+      <pre id="preview-data">
+        {JSON.stringify({ previewData: previewDataResult })}
+      </pre>
+    </main>
+  )
+}
+
+export const generateStaticParams = async () => {
+  const paths = [
+    {
+      route: [],
+    },
+    {
+      route: ['test'],
+    },
+    {
+      route: ['test-2'],
+    },
+  ]
+
+  return paths
+}