fix: handle parallel routes default layout (#150)

* fix: handle parallel routes default layout

* Fix tests

* Check that it's app router

* Add fs check

* Don't worry about missing default.meta

Author: ascorbic

src/build/content/prerendered.ts

@@ -50,11 +50,14 @@ export const copyPrerenderedContent = async (ctx: PluginContext): Promise<void>
     const manifest = await ctx.getPrerenderManifest()
 
     await Promise.all(
-      Object.entries(manifest.routes).map(async ([route, meta]) => {
+      Object.entries(manifest.routes).map(async ([route, meta]): Promise<void> => {
         const key = routeToFilePath(route)
         let value: CacheValue
-
         switch (true) {
+          // Parallel route default layout has no prerendered page
+          case meta.dataRoute?.endsWith('/default.rsc') &&
+            !existsSync(join(ctx.publishDir, 'server/app', `${key}.html`)):
+            return
           case meta.dataRoute?.endsWith('.json'):
             value = await buildPagesCacheValue(join(ctx.publishDir, 'server/pages', key))
             break

src/build/content/server.ts

@@ -107,7 +107,10 @@ export const writeTagsManifest = async (ctx: PluginContext): Promise<void> => {
         const meta = JSON.parse(file)
         tags = meta.headers['x-next-cache-tags']
       } catch {
-        console.log(`Unable to read cache tags for: ${path}`)
+        // Parallel route default layout has no prerendered page, so don't warn about it
+        if (!definition.dataRoute?.endsWith('/default.rsc')) {
+          console.log(`Unable to read cache tags for: ${path}`)
+        }
       }
     }
 

src/run/handlers/server.ts

@@ -61,10 +61,14 @@ export default async (request: Request) => {
   setVaryHeaders(response.headers, request, nextConfig)
 
   // Temporary workaround for an issue where sending a response with an empty
-  // body causes an unhandled error.
+  // body causes an unhandled error. This doesn't catch everything, but redirects are the
+  // most common case of sending empty bodies. We can't check it directly because these are streams.
+  // The side effect is that responses which do contain data will not be streamed to the client,
+  // but that's fine for redirects.
   // TODO: Remove once a fix has been rolled out.
   if (response.status > 300 && response.status < 400) {
-    return new Response(null, response)
+    const body = await response.text()
+    return new Response(body || null, response)
   }
 
   return response

tests/netlify-e2e.json

@@ -21,9 +21,9 @@
       ]
     },
     "test/e2e/app-dir/parallel-routes-and-interception/parallel-routes-and-interception.test.ts": {
-      "failed": [
-        "parallel-routes-and-interception route intercepting should render modal when paired with parallel routes",
-        "parallel-routes-and-interception route intercepting should support intercepting local dynamic sibling routes"
+      "failed": [],
+      "flakey": [
+        "parallel-routes-and-interception parallel routes should gracefully handle when two page segments match the `children` parallel slot"
       ]
     },
     "test/e2e/app-dir/error-boundary-navigation/override-node-env.test.ts": {
@@ -107,7 +107,14 @@
     "test/e2e/app-dir/metadata/metadata.test.ts": {
       "flakey": [
         "app dir - metadata opengraph should pick up opengraph-image and twitter-image as static metadata files",
-        "app dir - metadata static routes should have /favicon.ico as route"
+        "app dir - metadata static routes should have /favicon.ico as route",
+        "app dir - metadata static routes should have icons as route"
+      ]
+    },
+    "test/e2e/basepath.test.ts": {
+      "flakey": [
+        "basePath should not update URL for a 404",
+        "basePath should handle 404 urls that start with basePath"
       ]
     }
   },