Support instrumented params.then/catch/finally

unstubbable · unstubbable · commit 4c87b405bdc3 · 2025-05-19T12:43:20.000+02:00
diff --git a/packages/next/src/server/dynamic-rendering-utils.ts b/packages/next/src/server/dynamic-rendering-utils.ts
@@ -70,7 +70,7 @@ export function makeHangingPromise<T>(
     return new Proxy(hangingPromise, {
       ...handler,
       get: function get(target, prop, receiver) {
-        if (prop === 'then' || prop === 'status') {
+        if (prop === 'then' || prop === 'catch' || prop === 'finally') {
           // TODO: Maybe annotate dynamic access here.
         }
 
diff --git a/packages/next/src/server/request/params.ts b/packages/next/src/server/request/params.ts
@@ -214,20 +214,33 @@ function makeAbortingExoticParams(
     '`params`',
     {
       get: function get(target, prop, receiver) {
-        switch (prop) {
-          case 'then':
-          case 'status':
-            const dynamicAccessStore = dynamicAccessAsyncStorage.getStore()
-
-            if (dynamicAccessStore) {
-              dynamicAccessStore.abortController.abort(
-                new Error(`Accessed fallback \`params\` during prerendering.`)
-              )
-            }
-          // intentionally fallthrough
-          default:
-            return ReflectAdapter.get(target, prop, receiver)
+        if (prop === 'then' || prop === 'catch' || prop === 'finally') {
+          const originalMethod = ReflectAdapter.get(target, prop, receiver)
+
+          return {
+            [prop]: (...args: unknown[]) => {
+              const store = dynamicAccessAsyncStorage.getStore()
+
+              if (store)
+                store.abortController.abort(
+                  new Error(`Accessed fallback \`params\` during prerendering.`)
+                )
+
+              // Make sure the original method of the proxied promise is called.
+              // We don't use the returned new promise though. This is mostly
+              // needed to ensure the hanging promise rejection is triggered
+              // when the prerender signal is aborted.
+              originalMethod.apply(target, args)
+
+              // Instead, we return the instrumented proxied promise again, to
+              // ensure that it's also used when params.then(), params.catch(),
+              // or params.finally() is passed to another function.
+              return promise
+            },
+          }[prop]
         }
+
+        return ReflectAdapter.get(target, prop, receiver)
       },
     }
   )
diff --git a/test/e2e/app-dir/empty-fallback-shells/app/with-cached-io/without-suspense/params-then-in-page/[slug]/page.jsx b/test/e2e/app-dir/empty-fallback-shells/app/with-cached-io/without-suspense/params-then-in-page/[slug]/page.jsx
@@ -0,0 +1,15 @@
+import { CachedLastModified } from '../../../last-modified'
+
+export default async function Page({ params }) {
+  return (
+    <>
+      <CachedLastModified params={params.then((p) => p)} />
+      <CachedLastModified params={params.catch(() => {})} />
+      <CachedLastModified params={params.finally(() => {})} />
+    </>
+  )
+}
+
+export async function generateStaticParams() {
+  return [{ slug: 'foo' }]
+}
diff --git a/test/e2e/app-dir/empty-fallback-shells/empty-fallback-shells.test.ts b/test/e2e/app-dir/empty-fallback-shells/empty-fallback-shells.test.ts
@@ -95,7 +95,7 @@ describe('empty-fallback-shells', () => {
         })
       })
 
-      describe('and the params accessed in cached non-page function', () => {
+      describe('and the params accessed in a cached non-page function', () => {
         it('does not resume a postponed fallback shell', async () => {
           const res = await next.fetch(
             '/with-cached-io/without-suspense/params-not-in-page/bar'
@@ -114,6 +114,26 @@ describe('empty-fallback-shells', () => {
           }
         })
       })
+
+      describe('and params.then/catch/finally passed to a cached function', () => {
+        it('does not resume a postponed fallback shell', async () => {
+          const res = await next.fetch(
+            '/with-cached-io/without-suspense/params-then-in-page/bar'
+          )
+
+          const html = await res.text()
+          expect(html).toIncludeRepeated('data-testid="page-bar"', 3)
+          expect(html).toContain('layout-runtime')
+
+          if (isNextDeploy) {
+            expect(res.headers.get('x-matched-path')).toBe(
+              '/with-cached-io/without-suspense/params-then-in-page/[slug]'
+            )
+          } else {
+            expect(res.headers.get('x-nextjs-postponed')).not.toBe('1')
+          }
+        })
+      })
     })
   })
 })

Original file line number	Diff line number	Diff line change
`@@ -70,7 +70,7 @@ export function makeHangingPromise<T>(`
`70`	`70`	`return new Proxy(hangingPromise, {`
`71`	`71`	`...handler,`
`72`	`72`	`get: function get(target, prop, receiver) {`
`73`		`- if (prop === 'then' \|\| prop === 'status') {`
	`73`	`+ if (prop === 'then' \|\| prop === 'catch' \|\| prop === 'finally') {`
`74`	`74`	`// TODO: Maybe annotate dynamic access here.`
`75`	`75`	`}`
`76`	`76`