code · pull · Jul 23, 2026 · Jul 22, 2026
diff --git a/packages/react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack.js b/packages/react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack.js
@@ -263,8 +263,9 @@ export function getModuleDebugInfo<T>(
   const debugInfo: ReactDebugInfo = [];
   let i = 0;
   while (i < chunks.length) {
-    const chunkFilename = chunks[i++];
-    addChunkDebugInfo(debugInfo, chunkFilename);
+    const chunk = chunks[i++];
+    // A merged chunk is `[mergedChunkFilename, ...]`; use its own filename.
+    addChunkDebugInfo(debugInfo, typeof chunk === 'string' ? chunk : chunk[0]);
   }
   return debugInfo;
 }
diff --git a/...s/react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser.js b/...s/react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser.js
@@ -13,7 +13,9 @@ import type {
   ReactAsyncInfo,
 } from 'shared/ReactTypes';
 
-export function loadChunk(filename: string): Promise<mixed> {
+import type {Chunk} from '../shared/ReactFlightImportMetadata';
+
+export function loadChunk(filename: Chunk): Promise<mixed> {
   return __turbopack_load_by_url__(filename);
 }
 

diff --git a/...es/react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackServer.js b/...es/react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackServer.js
@@ -9,7 +9,9 @@
 
 import type {ReactDebugInfo} from 'shared/ReactTypes';
 
-export function loadChunk(filename: string): Promise<mixed> {
+import type {Chunk} from '../shared/ReactFlightImportMetadata';
+
+export function loadChunk(filename: Chunk): Promise<mixed> {
   return __turbopack_load_by_url__(filename);
 }
 

diff --git a/...ges/react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackServer.js b/...ges/react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackServer.js
@@ -9,21 +9,24 @@
 
 import {preinitScriptForSSR} from 'react-client/src/ReactFlightClientConfig';
 
+import type {Chunk} from '../shared/ReactFlightImportMetadata';
+
 export type ModuleLoading = null | {
   prefix: string,
   crossOrigin?: 'use-credentials' | '',
 };
 
 export function prepareDestinationWithChunks(
   moduleLoading: ModuleLoading,
-  // Chunks are single-indexed filenames
-  chunks: Array<string>,
+  chunks: Array<Chunk>,
   nonce: ?string,
 ) {
   if (moduleLoading !== null) {
     for (let i = 0; i < chunks.length; i++) {
+      const chunk = chunks[i];
+      // A merged chunk is `[mergedChunkFilename, ...]`; preinit its own URL.
       preinitScriptForSSR(
-        moduleLoading.prefix + chunks[i],
+        moduleLoading.prefix + (typeof chunk === 'string' ? chunk : chunk[0]),
         nonce,
         moduleLoading.crossOrigin,
       );

diff --git a/packages/react-server-dom-turbopack/src/shared/ReactFlightImportMetadata.js b/packages/react-server-dom-turbopack/src/shared/ReactFlightImportMetadata.js
@@ -7,10 +7,20 @@
  * @flow
  */
 
+// A chunk is either a plain chunk filename, or a merged chunk that bundles
+// several component chunks together, emitted as
+// `[mergedChunkFilename, componentChunkFilenames, componentChunkSizes]`.
+export type Chunk =
+  | string
+  | [
+      /* merged chunk filename */ string,
+      /* component chunk filenames */ Array<string>,
+      /* component chunk sizes */ Array<number>,
+    ];
+
 export type ImportManifestEntry = {
   id: string,
-  // chunks is an array of filenames
-  chunks: Array<string>,
+  chunks: Array<Chunk>,
   name: string,
   async?: boolean,
 };
@@ -20,11 +30,11 @@ export type ImportManifestEntry = {
 export type ImportMetadata =
   | [
       /* id */ string,
-      /* chunk filenames */ Array<string>,
+      /* chunks */ Array<Chunk>,
       /* name */ string,
       /* async */ 1,
     ]
-  | [/* id */ string, /* chunk filenames */ Array<string>, /* name */ string];
+  | [/* id */ string, /* chunks */ Array<Chunk>, /* name */ string];
 
 export const ID = 0;
 export const CHUNKS = 1;

diff --git a/scripts/flow/environment.js b/scripts/flow/environment.js
@@ -146,7 +146,11 @@ declare const __webpack_require__: ((id: string) => any) & {
   u: string => string,
 };
 
-declare function __turbopack_load_by_url__(id: string): Promise<mixed>;
+// A chunk id is a plain filename, or a merged chunk emitted as
+// `[mergedChunkFilename, componentChunkFilenames, componentChunkSizes]`.
+declare function __turbopack_load_by_url__(
+  id: string | [string, Array<string>, Array<number>],
+): Promise<mixed>;
 declare const __turbopack_require__: ((id: string) => any) & {
   u: string => string,
 };