fix(manifest): avoid chunks with same name overwriting one another

close #1632

packages/vite/src/node/plugins/manifest.ts

@@ -1,15 +1,20 @@
+import path from 'path'
 import { ResolvedConfig } from '..'
 import { Plugin } from '../plugin'
 
+type Manifest = Record<string, ManifestEntry>
+
+interface ManifestEntry {
+  file: string
+  facadeModuleId?: string
+  isEntry?: boolean
+  isDynamicEntry?: boolean
+  imports?: string[]
+  dynamicImports?: string[]
+}
+
 export function manifestPlugin(config: ResolvedConfig): Plugin {
-  const manifest: Record<
-    string,
-    {
-      file: string
-      imports?: string[],
-      dynamicImports?: string[]
-    }
-  > = {}
+  const manifest: Manifest = {}
 
   let outputCount = 0
 
@@ -20,18 +25,41 @@ export function manifestPlugin(config: ResolvedConfig): Plugin {
         const chunk = bundle[file]
         if (chunk.type === 'chunk') {
           if (chunk.isEntry || chunk.isDynamicEntry) {
-            const name =
+            let name =
               format === 'system' && !chunk.name.includes('-legacy')
                 ? chunk.name + '-legacy'
                 : chunk.name
-            manifest[name + '.js'] = {
+            let dedupeIndex = 0
+            while (name + '.js' in manifest) {
+              name = `${name}-${++dedupeIndex}`
+            }
+            const entry: ManifestEntry = {
+              isEntry: chunk.isEntry,
+              isDynamicEntry: chunk.isDynamicEntry,
               file: chunk.fileName,
               imports: chunk.imports,
               dynamicImports: chunk.dynamicImports
             }
+
+            if (
+              chunk.facadeModuleId &&
+              chunk.facadeModuleId.startsWith(config.root)
+            ) {
+              entry.facadeModuleId = chunk.facadeModuleId.slice(
+                config.root.length + 1
+              )
+            }
+
+            manifest[name + '.js'] = entry
           }
         } else if (chunk.name) {
-          manifest[chunk.name] = { file: chunk.fileName }
+          const ext = path.extname(chunk.name) || ''
+          let name = chunk.name.slice(0, -ext.length)
+          let dedupeIndex = 0
+          while (name + ext in manifest) {
+            name = `${name}-${++dedupeIndex}`
+          }
+          manifest[name + ext] = { file: chunk.fileName }
         }
       }