fix: revert sourcemp handling for webpack and improve tests

package.json

@@ -44,6 +44,7 @@
     "fs-extra": "^10.0.0",
     "jest": "^27.2.0",
     "jiti": "^1.12.0",
+    "magic-string": "^0.25.7",
     "rollup": "^2.56.3",
     "standard-version": "^9.3.1",
     "ts-jest": "^27.0.5",

src/webpack/loaders/transform.ts

@@ -19,23 +19,7 @@ export default async function transform (this: LoaderContext<any>, source: strin
   if (res == null) {
     callback(null, source, map)
   } else if (typeof res !== 'string') {
-    // only pass sourcemap when sourcemap is provided upstream
-    const newMap = map == null ? map : (res.map || map)
-    // clean up nullish sources produced by magic-string
-    if (newMap && Array.isArray(newMap.sources)) {
-      const excluded: number[] = []
-      newMap.sources = newMap.sources.filter((i:any, idx:number) => {
-        if (i == null) {
-          excluded.push(idx)
-          return false
-        }
-        return true
-      })
-      newMap.sources = newMap.sources.filter((_: any, idx: number) => {
-        return !excluded.includes(idx)
-      })
-    }
-    callback(null, res.code, newMap)
+    callback(null, res.code, map == null ? map : (res.map || map))
   } else {
     callback(null, res, map)
   }

test/fixtures/transform/rollup.config.js

@@ -3,7 +3,8 @@ const { rollup } = require('./unplugin')
 export default {
   input: './src/main.js',
   output: {
-    dir: './dist/rollup'
+    dir: './dist/rollup',
+    sourcemap: true
   },
   plugins: [
     rollup({ msg: 'Rollup' })

test/fixtures/transform/unplugin.js

@@ -1,13 +1,27 @@
 const { createUnplugin } = require('unplugin')
+const MagicString = require('magic-string')
 
 module.exports = createUnplugin((options) => {
   return {
     name: 'transform-fixture',
     transformInclude (id) {
       return id.match(/[/\\]target\.js$/)
     },
-    transform (code) {
-      return code.replace('__UNPLUGIN__', `[Injected ${options.msg}]`)
+    transform (code, id) {
+      const s = new MagicString(code)
+      const index = code.indexOf('__UNPLUGIN__')
+      if (index === -1) {
+        return null
+      }
+
+      s.overwrite(index, index + '__UNPLUGIN__'.length, `[Injected ${options.msg}]`)
+      return {
+        code: s.toString(),
+        map: s.generateMap({
+          source: id,
+          includeContent: true
+        })
+      }
     }
   }
 })

test/fixtures/transform/vite.config.js

@@ -12,6 +12,7 @@ module.exports = {
       name: 'main',
       fileName: 'main.js'
     },
-    outDir: 'dist/vite'
+    outDir: 'dist/vite',
+    sourcemap: true
   }
 }

test/fixtures/transform/webpack.config.js

@@ -10,5 +10,6 @@ module.exports = {
   },
   plugins: [
     webpack({ msg: 'Webpack' })
-  ]
+  ],
+  devtool: 'source-map'
 }

yarn.lock

@@ -3745,6 +3745,13 @@ lru-cache@^6.0.0:
   dependencies:
     yallist "^4.0.0"
 
+magic-string@^0.25.7:
+  version "0.25.7"
+  resolved "https://registry.yarnpkg.com/magic-string/-/magic-string-0.25.7.tgz#3f497d6fd34c669c6798dcb821f2ef31f5445051"
+  integrity sha512-4CrMT5DOHTDk4HYDlzmwu4FVCcIYI8gauveasrdCu2IKIFOJ3f0v/8MDGJCDL9oD2ppz/Av1b0Nj345H9M+XIA==
+  dependencies:
+    sourcemap-codec "^1.4.4"
+
 make-dir@^3.0.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/make-dir/-/make-dir-3.1.0.tgz#415e967046b3a7f1d185277d84aa58203726a13f"
@@ -4712,6 +4719,11 @@ source-map@^0.7.3, source-map@~0.7.2:
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.7.3.tgz#5302f8169031735226544092e64981f751750383"
   integrity sha512-CkCj6giN3S+n9qrYiBTX5gystlENnRW5jZeNLHpe6aue+SrHcG5VYwujhW9s4dY31mEGsxBDrHR6oI69fTXsaQ==
 
+sourcemap-codec@^1.4.4:
+  version "1.4.8"
+  resolved "https://registry.yarnpkg.com/sourcemap-codec/-/sourcemap-codec-1.4.8.tgz#ea804bd94857402e6992d05a38ef1ae35a9ab4c4"
+  integrity sha512-9NykojV5Uih4lgo5So5dtw+f0JgJX30KCNI8gwhz2J9A15wD0Ml6tjHKwf6fTSa6fAdVBdZeNOs9eJ71qCk8vA==
+
 spdx-correct@^3.0.0:
   version "3.1.1"
   resolved "https://registry.yarnpkg.com/spdx-correct/-/spdx-correct-3.1.1.tgz#dece81ac9c1e6713e5f7d1b6f17d468fa53d89a9"