Fix edge entry layer resolution bug (#41757)

By default the edge page entry is in the client layer because it bundles Next.js. It's a virtual loader (edge-ssr-loader) but that makes the SWC loader think the page's source is a client component.

We use the resource query `__edge_ssr_entry__` to convert it to the server layer but we need to add that condition to the SWC loader too.

## Bug

- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have a 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 a helpful link attached, see `contributing.md`

## Documentation / Examples

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

packages/next/build/webpack-config.ts

@@ -729,6 +729,16 @@ export default async function getBaseWebpackConfig(
     babel: getBabelOrSwcLoader(),
   }
 
+  const swcLoaderForRSC = hasServerComponents
+    ? useSWCLoader
+      ? getSwcLoader({ isServerLayer: true })
+      : // When using Babel, we will have to add the SWC loader
+        // as an additional pass to handle RSC correctly.
+        // This will cause some performance overhead but
+        // acceptable as Babel will not be recommended.
+        [getSwcLoader({ isServerLayer: true }), getBabelLoader()]
+    : []
+
   const pageExtensions = config.pageExtensions
 
   const outputPath =
@@ -1789,16 +1799,12 @@ export default async function getBaseWebpackConfig(
                     test: codeCondition.test,
                     issuerLayer: WEBPACK_LAYERS.server,
                     exclude: [staticGenerationAsyncStorageRegex],
-                    use: useSWCLoader
-                      ? getSwcLoader({ isServerLayer: true })
-                      : // When using Babel, we will have to add the SWC loader
-                        // as an additional pass to handle RSC correctly.
-                        // This will cause some performance overhead but
-                        // acceptable as Babel will not be recommended.
-                        [
-                          getSwcLoader({ isServerLayer: true }),
-                          getBabelLoader(),
-                        ],
+                    use: swcLoaderForRSC,
+                  },
+                  {
+                    test: codeCondition.test,
+                    resourceQuery: /__edge_ssr_entry__/,
+                    use: swcLoaderForRSC,
                   },
                 ]
               : []),

test/e2e/app-dir/app/app/edge-apis/cookies/page.js

@@ -0,0 +1,8 @@
+import { cookies } from 'next/headers'
+
+export const runtime = 'experimental-edge'
+
+export default function Page() {
+  cookies()
+  return <h1>Hello!</h1>
+}

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

@@ -955,6 +955,11 @@ describe('app dir', () => {
             }
           })
 
+          it('should retrieve cookies in a server component in the edge runtime', async () => {
+            const res = await fetchViaHTTP(next.url, '/edge-apis/cookies')
+            expect(await res.text()).toInclude('Hello')
+          })
+
           it('should access cookies on <Link /> navigation', async () => {
             const browser = await webdriver(next.url, '/navigation')