fix(worker): hide "The emitted file overwrites" warning if the content is same

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

@@ -1,6 +1,6 @@
 import path from 'node:path'
 import MagicString from 'magic-string'
-import type { EmittedAsset, OutputChunk } from 'rollup'
+import type { OutputChunk } from 'rollup'
 import type { ResolvedConfig } from '../config'
 import type { Plugin } from '../plugin'
 import type { ViteDevServer } from '../server'
@@ -14,9 +14,11 @@ import {
 import { cleanUrl } from '../../shared/utils'
 import { fileToUrl } from './asset'
 
+type WorkerBundleAsset = { fileName: string; source: string | Uint8Array }
+
 interface WorkerCache {
  // save worker all emit chunk avoid rollup make the same asset unique.
- assets: Map<string, EmittedAsset>
+ assets: Map<string, WorkerBundleAsset>
 
  // worker bundle don't deps on any more worker runtime info an id only had a result.
  // save worker bundled file id to avoid repeated execution of bundles
@@ -38,11 +40,10 @@ const workerCache = new WeakMap<ResolvedConfig, WorkerCache>()
 
 function saveEmitWorkerAsset(
  config: ResolvedConfig,
- asset: EmittedAsset,
+ asset: WorkerBundleAsset,
 ): void {
- const fileName = asset.fileName!
  const workerMap = workerCache.get(config.mainConfig || config)!
- workerMap.assets.set(fileName, asset)
+ workerMap.assets.set(asset.fileName, asset)
 }
 
 async function bundleWorkerEntry(
@@ -96,7 +97,6 @@ async function bundleWorkerEntry(
  saveEmitWorkerAsset(config, {
  fileName: outputChunk.fileName,
  source: outputChunk.code,
- type: 'asset',
  })
  }
  })
@@ -121,7 +121,6 @@ function emitSourcemapForWorkerEntry(
  const mapFileName = chunk.fileName + '.map'
  saveEmitWorkerAsset(config, {
  fileName: mapFileName,
- type: 'asset',
  source: data,
  })
  }
@@ -156,7 +155,6 @@ export async function workerFileToUrl(
  saveEmitWorkerAsset(config, {
  fileName,
  source: outputChunk.code,
- type: 'asset',
  })
  workerMap.bundle.set(id, fileName)
  }
@@ -410,16 +408,42 @@ export function webWorkerPlugin(config: ResolvedConfig): Plugin {
  return result()
  },
 
- generateBundle(opts) {
+ generateBundle(opts, bundle) {
  // @ts-expect-error asset emits are skipped in legacy bundle
  if (opts.__vite_skip_asset_emit__ || isWorker) {
  return
  }
  const workerMap = workerCache.get(config)!
  workerMap.assets.forEach((asset) => {
- this.emitFile(asset)
- workerMap.assets.delete(asset.fileName!)
+ const duplicateAsset = bundle[asset.fileName]
+ if (duplicateAsset) {
+ const content =
+ duplicateAsset.type === 'asset'
+ ? duplicateAsset.source
+ : duplicateAsset.code
+ // don't emit if the file name and the content is same
+ if (isSameContent(content, asset.source)) {
+ return
+ }
+ }
+
+ this.emitFile({
+ type: 'asset',
+ fileName: asset.fileName,
+ source: asset.source,
+ })
  })
+ workerMap.assets.clear()
  },
  }
 }
+
+function isSameContent(a: string | Uint8Array, b: string | Uint8Array) {
+ if (typeof a === 'string') {
+ if (typeof b === 'string') {
+ return a === b
+ }
+ return Buffer.from(a).equals(b)
+ }
+ return Buffer.from(b).equals(a)
+}