[dynamicIO] routes with dynamic segments should be able to be static in dev (#76691)

Dev mode reports static/dynamic behavior using a heuristic when
dynamicIO is enabled. The heuristic previously incorrectly marked routes
as dynamic when they were in fact static as a consequence of refactoring
metadata to support streaming. This update adjust the heuristic to not
incorrectly assume dynamic in these situations.

The root cause is that errors in `onError` cannot be assumed to be valid
if the render has already aborted

Closes NAR-112

Author: gnoff

packages/next/src/export/index.ts

@@ -387,11 +387,7 @@ async function exportAppImpl(
     strictNextHead: nextConfig.experimental.strictNextHead ?? true,
     deploymentId: nextConfig.deploymentId,
     htmlLimitedBots: nextConfig.htmlLimitedBots.source,
-    streamingMetadata:
-      // Disable streaming metadata when dynamic IO is enabled.
-      // FIXME: remove dynamic IO guard once we fixed the dynamic indicator case.
-      // test/e2e/app-dir/dynamic-io/dynamic-io.test.ts - should not have static indicator on not-found route
-      !nextConfig.experimental.dynamicIO,
+    streamingMetadata: true,
     experimental: {
       clientTraceMetadata: nextConfig.experimental.clientTraceMetadata,
       expireTime: nextConfig.expireTime,

packages/next/src/export/worker.ts

@@ -425,11 +425,7 @@ export async function exportPages(
             enableExperimentalReact: needsExperimentalReact(nextConfig),
             sriEnabled: Boolean(nextConfig.experimental.sri?.algorithm),
             buildId: input.buildId,
-            streamingMetadata:
-              // Disable streaming metadata when dynamic IO is enabled.
-              // FIXME: remove dynamic IO guard once we fixed the dynamic indicator case.
-              // test/e2e/app-dir/dynamic-io/dynamic-io.test.ts - should not have static indicator on not-found route
-              !nextConfig.experimental.dynamicIO,
+            streamingMetadata: true,
           }),
           // If exporting the page takes longer than the timeout, reject the promise.
           new Promise((_, reject) => {

packages/next/src/server/app-render/app-render.tsx

@@ -2446,6 +2446,7 @@ async function spawnDynamicValidationInDev(
     }
   )
 
+  let rootDidError = false
   const serverPhasedStream = serverPrerenderStreamResult.asPhasedStream()
   try {
     const prerender = require('react-dom/static.edge')
@@ -2476,7 +2477,12 @@ async function spawnDynamicValidationInDev(
                 isPrerenderInterruptedError(err) ||
                 finalClientController.signal.aborted
               ) {
-                requestStore.usedDynamic = true
+                if (!rootDidError) {
+                  // If the root errored before we observe this error then it wasn't caused by something dynamic.
+                  // If the root did not error or is erroring because of a sync dynamic API or a prerender interrupt error
+                  // then we are a dynamic route.
+                  requestStore.usedDynamic = true
+                }
 
                 const componentStack = errorInfo.componentStack
                 if (typeof componentStack === 'string') {
@@ -2501,6 +2507,7 @@ async function spawnDynamicValidationInDev(
       }
     )
   } catch (err) {
+    rootDidError = true
     if (
       isPrerenderInterruptedError(err) ||
       finalClientController.signal.aborted

packages/next/src/server/base-server.ts

@@ -600,11 +600,7 @@ export default abstract class Server<
       isExperimentalCompile: this.nextConfig.experimental.isExperimentalCompile,
       // `htmlLimitedBots` is passed to server as serialized config in string format
       htmlLimitedBots: this.nextConfig.htmlLimitedBots,
-      streamingMetadata:
-        // Disable streaming metadata when dynamic IO is enabled.
-        // FIXME: remove dynamic IO guard once we fixed the dynamic indicator case.
-        // test/e2e/app-dir/dynamic-io/dynamic-io.test.ts - should not have static indicator on not-found route
-        !this.nextConfig.experimental.dynamicIO,
+      streamingMetadata: true,
       experimental: {
         expireTime: this.nextConfig.expireTime,
         clientTraceMetadata: this.nextConfig.experimental.clientTraceMetadata,

test/e2e/app-dir/dynamic-io-errors/dynamic-io-errors.test.ts

@@ -159,10 +159,16 @@ function runTests(options: { withMinification: boolean }) {
           throw new Error('expected build not to fail for fully static project')
         }
 
-        expect(next.cliOutput).toContain('ƒ / ')
-        const $ = await next.render$('/')
-        expect($('#dynamic').text()).toBe('Dynamic')
-        expect($('[data-fallback]').length).toBe(0)
+        if (WITH_PPR) {
+          expect(next.cliOutput).toContain('◐ / ')
+          const $ = await next.render$('/')
+          expect($('#dynamic').text()).toBe('Dynamic')
+          expect($('[data-fallback]').length).toBe(1)
+        } else {
+          expect(next.cliOutput).toContain('ƒ / ')
+          const $ = await next.render$('/')
+          expect($('#dynamic').text()).toBe('Dynamic')
+        }
       })
     })