Include page for export errors for easier debugging (#32013)

This makes sure to include the `page` for dynamic routes when they encounter an error during prerendering as we currently only include the `path`, e.g. before we would only show `/blog/first` and now we show `/blog/[slug]: /blog/first` 

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `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`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `yarn lint`

packages/next/export/index.ts

@@ -600,7 +600,10 @@ export default async function exportApp(
                 ampValidationResult.errors.length > 0)
           }
           renderError = renderError || !!result.error
-          if (!!result.error) errorPaths.push(path)
+          if (!!result.error) {
+            const { page } = pathMap
+            errorPaths.push(page !== path ? `${page}: ${path}` : path)
+          }
 
           if (options.buildExport && configuration) {
             if (typeof result.fromBuildExportRevalidate !== 'undefined') {

test/integration/auto-export-query-error/test/index.test.js

@@ -20,7 +20,6 @@ const runTests = () => {
     expect(stderr).not.toContain('/amp')
     expect(stderr).not.toContain('/ssr')
     expect(stderr).not.toContain('/ssg')
-    expect(stderr).not.toContain('/hello')
   })
 }
 

test/integration/handles-export-errors/pages/blog/[slug].js

@@ -0,0 +1,16 @@
+export default function Page() {
+  throw new Error('oops')
+}
+
+export function getStaticProps() {
+  return {
+    props: {},
+  }
+}
+
+export function getStaticPaths() {
+  return {
+    paths: ['/blog/first', '/blog/second'],
+    fallback: false,
+  }
+}

test/integration/handles-export-errors/test/index.test.js

@@ -19,5 +19,7 @@ describe('Handles Errors During Export', () => {
     expect(stderr).toContain('/page-2')
     expect(stderr).toContain('/page-3')
     expect(stderr).toContain('/page-13')
+    expect(stderr).toContain('/blog/[slug]: /blog/first')
+    expect(stderr).toContain('/blog/[slug]: /blog/second')
   })
 })