Refactor: create server module map only once

Small follow-up to #86591.

We don't need to recreate the server module map proxy every time we set
the manifests singleton. Instead, we can just update the underlying
server actions manifest, and the server module map can read the current
manifest from the singleton.

Author: unstubbable

packages/next/src/server/app-render/action-utils.ts

@@ -1,4 +1,3 @@
-import type { ActionManifest } from '../../build/webpack/plugins/flight-client-entry-plugin'
 import { normalizeAppPath } from '../../shared/lib/router/utils/app-paths'
 import { pathHasPrefix } from '../../shared/lib/router/utils/path-has-prefix'
 import { removePathPrefix } from '../../shared/lib/router/utils/remove-path-prefix'
@@ -18,17 +17,13 @@ export interface ServerModuleMap {
 // Server Reference Manifest similar to our client module map.
 // This is because our manifest contains a lot of internal Next.js data that
 // are relevant to the runtime, workers, etc. that React doesn't need to know.
-export function createServerModuleMap({
-  serverActionsManifest,
-}: {
-  serverActionsManifest: ActionManifest
-}): ServerModuleMap {
+export function createServerModuleMap(): ServerModuleMap {
   return new Proxy(
     {},
     {
       get: (_, id: string) => {
         const workers =
-          serverActionsManifest[
+          getServerActionsManifest()[
             process.env.NEXT_RUNTIME === 'edge' ? 'edge' : 'node'
           ]?.[id]?.workers
 

packages/next/src/server/app-render/manifests-singleton.ts

@@ -180,10 +180,6 @@ export function setManifestsSingleton({
     )
 
     existingSingleton.serverActionsManifest = serverActionsManifest
-
-    existingSingleton.serverModuleMap = createServerModuleMap({
-      serverActionsManifest,
-    })
   } else {
     const clientReferenceManifestsPerRoute = new Map<
       string,
@@ -194,15 +190,11 @@ export function setManifestsSingleton({
       clientReferenceManifestsPerRoute
     )
 
-    const serverModuleMap = createServerModuleMap({
-      serverActionsManifest,
-    })
-
     globalThisWithManifests[MANIFESTS_SINGLETON] = {
       clientReferenceManifestsPerRoute,
       proxiedClientReferenceManifest,
       serverActionsManifest,
-      serverModuleMap,
+      serverModuleMap: createServerModuleMap(),
     }
   }
 }