From 23440e9564fb794d904a905e82eb1a475e22d4be Mon Sep 17 00:00:00 2001
From: patak-dev <matias.capeletto@gmail.com>
Date: Tue, 1 Mar 2022 12:00:07 +0100
Subject: [PATCH] feat: support user manualChunks composition

---
 packages/playground/vue/vite.config.ts        | 12 ++++++++-
 .../vite/src/node/plugins/splitVendorChunk.ts | 27 ++++++++++++++++---
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/packages/playground/vue/vite.config.ts b/packages/playground/vue/vite.config.ts
index a9ca552cbccda2..f99a68ce8b6b10 100644
--- a/packages/playground/vue/vite.config.ts
+++ b/packages/playground/vue/vite.config.ts
@@ -17,7 +17,17 @@ export default defineConfig({
   ],
   build: {
     // to make tests faster
-    minify: false
+    minify: false,
+    rollupOptions: {
+      output: {
+        // Test splitVendorChunkPlugin composition
+        manualChunks(id) {
+          if (id.includes('src-import')) {
+            return 'src-import'
+          }
+        }
+      }
+    }
   },
   css: {
     modules: {
diff --git a/packages/vite/src/node/plugins/splitVendorChunk.ts b/packages/vite/src/node/plugins/splitVendorChunk.ts
index 09246e14e35234..3f7c16067a5f8e 100644
--- a/packages/vite/src/node/plugins/splitVendorChunk.ts
+++ b/packages/vite/src/node/plugins/splitVendorChunk.ts
@@ -1,6 +1,11 @@
 import type { UserConfig } from '../../node'
 import type { Plugin } from '../plugin'
-import type { OutputOptions, GetManualChunk, GetModuleInfo } from 'rollup'
+import type {
+  OutputOptions,
+  GetManualChunk,
+  GetManualChunkApi,
+  GetModuleInfo
+} from 'rollup'
 import { isCSSRequest } from './css'
 
 // Use splitVendorChunkPlugin() to get the same manualChunks strategy as Vite 2.7
@@ -91,13 +96,29 @@ export function splitVendorChunkPlugin(): Plugin {
       if (outputs) {
         outputs = Array.isArray(outputs) ? outputs : [outputs]
         for (const output of outputs) {
-          output.manualChunks = createSplitVendorChunk(output, config)
+          const viteManualChunks = createSplitVendorChunk(output, config)
+          if (viteManualChunks) {
+            if (output.manualChunks) {
+              if (typeof output.manualChunks === 'function') {
+                const userManualChunks = output.manualChunks
+                output.manualChunks = (id: string, api: GetManualChunkApi) => {
+                  return userManualChunks(id, api) ?? viteManualChunks(id, api)
+                }
+              }
+              // else, leave the object form of manualChunks untouched, as
+              // we can't safely replicate rollup handling.
+            } else {
+              output.manualChunks = viteManualChunks
+            }
+          }
         }
       } else {
         return {
           build: {
             rollupOptions: {
-              manualChunks: createSplitVendorChunk({}, config)
+              output: {
+                manualChunks: createSplitVendorChunk({}, config)
+              }
             }
           }
         }