refactor: consolidate rscBundle into bundles map and delay fileName resolution

- Replace `rscBundle` with `bundles: Record<string, OutputBundle>` in RscPluginManager
- Lookup fileName from bundles in writeEnvironmentImportsManifest instead of mutating meta
- Remove generateBundle hook from import-environment plugin (no longer needed)
- Remove unused fileName field from EnvironmentImportMeta type

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: hi-ogawa

packages/plugin-rsc/src/plugin.ts

@@ -117,7 +117,7 @@ export type { RscPluginManager }
 class RscPluginManager {
   server!: ViteDevServer
   config!: ResolvedConfig
-  rscBundle!: Rollup.OutputBundle
+  bundles: Record<string, Rollup.OutputBundle> = {}
   buildAssetsManifest: AssetsManifest | undefined
   isScanBuild: boolean = false
   clientReferenceMetaMap: Record<string, ClientReferenceMeta> = {}
@@ -172,15 +172,21 @@ class RscPluginManager {
 
       let code = 'export default {\n'
       for (const [resolvedId, meta] of Object.entries(imports)) {
-        if (!meta.fileName) {
+        // Lookup fileName from bundle
+        const bundle = this.bundles[meta.targetEnv]
+        const chunk = Object.values(bundle ?? {}).find(
+          (c) =>
+            c.type === 'chunk' && c.isEntry && c.facadeModuleId === resolvedId,
+        )
+        if (!chunk) {
           throw new Error(
             `[vite-rsc] missing output for environment import: ${resolvedId}`,
           )
         }
         const targetOutDir =
           this.config.environments[meta.targetEnv]!.build.outDir
         const relativePath = normalizeRelativePath(
-          path.relative(sourceOutDir, path.join(targetOutDir, meta.fileName)),
+          path.relative(sourceOutDir, path.join(targetOutDir, chunk.fileName)),
         )
         // Use relative ID for stable builds across different machines
         const relativeId = this.toRelativeId(resolvedId)
@@ -1069,9 +1075,7 @@ export function createRpcClient(params) {
       // client build
       generateBundle(_options, bundle) {
         // copy assets from rsc build to client build
-        if (this.environment.name === 'rsc') {
-          manager.rscBundle = bundle
-        }
+        manager.bundles[this.environment.name] = bundle
 
         if (this.environment.name === 'client') {
           const filterAssets =
@@ -1081,7 +1085,7 @@ export function createRpcClient(params) {
             typeof rscBuildOptions.manifest === 'string'
               ? rscBuildOptions.manifest
               : rscBuildOptions.manifest && '.vite/manifest.json'
-          for (const asset of Object.values(manager.rscBundle)) {
+          for (const asset of Object.values(manager.bundles['rsc']!)) {
             if (asset.fileName === rscViteManifest) continue
             if (asset.type === 'asset' && filterAssets(asset.fileName)) {
               this.emitFile({
@@ -1093,7 +1097,7 @@ export function createRpcClient(params) {
           }
 
           const serverResources: Record<string, AssetDeps> = {}
-          const rscAssetDeps = collectAssetDeps(manager.rscBundle)
+          const rscAssetDeps = collectAssetDeps(manager.bundles['rsc']!)
           for (const [id, meta] of Object.entries(
             manager.serverResourcesMetaMap,
           )) {

packages/plugin-rsc/src/plugins/import-environment.ts

@@ -21,7 +21,6 @@ export type EnvironmentImportMeta = {
   targetEnv: string
   sourceEnv: string
   specifier: string
-  fileName?: string
 }
 
 export function vitePluginImportEnvironment(
@@ -132,13 +131,11 @@ export function vitePluginImportEnvironment(
               resolvedId = resolved.id
             }
 
-            // TODO: environmentImportMetaMap structure seems still awkward
-            // should be [sourceEnv][targetEnv][resolvedId]
-
+            // TODO: environmentImportMetaMap structure should be [sourceEnv][targetEnv][resolvedId]
             // Track discovered entry, keyed by [sourceEnv][resolvedId]
             const sourceEnv = this.environment.name
             manager.environmentImportMetaMap[sourceEnv] ??= {}
-            manager.environmentImportMetaMap[sourceEnv]![resolvedId] ??= {
+            manager.environmentImportMetaMap[sourceEnv]![resolvedId] = {
               resolvedId,
               targetEnv: environmentName,
               sourceEnv,
@@ -186,29 +183,6 @@ export function vitePluginImportEnvironment(
         }
         return
       },
-
-      generateBundle(_options, bundle) {
-        if (this.environment.name === 'client') return
-
-        // TODO: delay `fileName` assigment to right before writeEnvironmentImportsManifest
-        // TODO: we can just hold old `bundles: Record<string, ..>` in manager
-
-        // Track output filenames for discovered environment imports
-        // Only set fileName when this bundle's environment matches the target
-        for (const [fileName, chunk] of Object.entries(bundle)) {
-          if (chunk.type === 'chunk' && chunk.isEntry && chunk.facadeModuleId) {
-            const resolvedId = chunk.facadeModuleId
-            for (const imports of Object.values(
-              manager.environmentImportMetaMap,
-            )) {
-              const meta = imports[resolvedId]
-              if (meta && meta.targetEnv === this.environment.name) {
-                meta.fileName = fileName
-              }
-            }
-          }
-        }
-      },
     },
     createVirtualPlugin(
       ENV_IMPORTS_ENTRY_FALLBACK.slice('virtual:'.length),