feat!(coverage): v8 to support only AST based remapping (#8064)

Author: AriPerkkio

docs/config/index.md

@@ -1628,51 +1628,11 @@ Sets thresholds to 100 for files matching the glob pattern.
 }
 ```
 
-#### coverage.ignoreEmptyLines
-
-- **Type:** `boolean`
-- **Default:** `true` (`false` in v1)
-- **Available for providers:** `'v8'`
-- **CLI:** `--coverage.ignoreEmptyLines=<boolean>`
-
-Ignore empty lines, comments and other non-runtime code, e.g. Typescript types. Requires `experimentalAstAwareRemapping: false`.
-
-This option works only if the used compiler removes comments and other non-runtime code from the transpiled code.
-By default Vite uses ESBuild which removes comments and Typescript types from `.ts`, `.tsx` and `.jsx` files.
-
-If you want to apply ESBuild to other files as well, define them in [`esbuild` options](https://vitejs.dev/config/shared-options.html#esbuild):
-
-```ts
-import { defineConfig } from 'vitest/config'
-
-export default defineConfig({
-  esbuild: {
-    // Transpile all files with ESBuild to remove comments from code coverage.
-    // Required for `test.coverage.ignoreEmptyLines` to work:
-    include: ['**/*.js', '**/*.jsx', '**/*.mjs', '**/*.ts', '**/*.tsx'],
-  },
-  test: {
-    coverage: {
-      provider: 'v8',
-      ignoreEmptyLines: true,
-    },
-  },
-})
-```
-#### coverage.experimentalAstAwareRemapping
-
-- **Type:** `boolean`
-- **Default:** `false`
-- **Available for providers:** `'v8'`
-- **CLI:** `--coverage.experimentalAstAwareRemapping=<boolean>`
-
-Remap coverage with experimental AST based analysis. Provides more accurate results compared to default mode.
-
 #### coverage.ignoreClassMethods
 
 - **Type:** `string[]`
 - **Default:** `[]`
-- **Available for providers:** `'istanbul'`
+- **Available for providers:** `'v8' | 'istanbul'`
 - **CLI:** `--coverage.ignoreClassMethods=<method>`
 
 Set to array of class method names to ignore for coverage.

docs/guide/coverage.md

@@ -336,9 +336,8 @@ Please refer to the type definition for more details.
 
 Both coverage providers have their own ways how to ignore code from coverage reports:
 
-- [`v8`](https://github.com/istanbuljs/v8-to-istanbul#ignoring-uncovered-lines)
+- [`v8`](https://github.com/AriPerkkio/ast-v8-to-istanbul?tab=readme-ov-file#ignoring-code)
 - [`istanbul`](https://github.com/istanbuljs/nyc#parsing-hints-ignoring-lines)
-- `v8` with [`experimentalAstAwareRemapping: true`](https://vitest.dev/config/#coverage-experimentalAstAwareRemapping) see [ast-v8-to-istanbul | Ignoring code](https://github.com/AriPerkkio/ast-v8-to-istanbul?tab=readme-ov-file#ignoring-code)
 
 When using TypeScript the source codes are transpiled using `esbuild`, which strips all comments from the source codes ([esbuild#516](https://github.com/evanw/esbuild/issues/516)).
 Comments which are considered as [legal comments](https://esbuild.github.io/api/#legal-comments) are preserved.

docs/guide/migration.md

@@ -21,6 +21,21 @@ export default defineConfig({
 })
 ```
 
+### V8 Code Coverage Major Changes
+
+Vitest's V8 code coverage provider is now using more accurate coverage result remapping logic.
+It is expected for users to see changes in their coverage reports when updating from Vitest v3.
+
+In the past Vitest used [`v8-to-istanbul`](https://github.com/istanbuljs/v8-to-istanbul) for remapping V8 coverage results into your source files.
+This method wasn't very accurate and provided plenty of false positives in the coverage reports.
+We've now developed a new package that utilizes AST based analysis for the V8 coverage.
+This allows V8 reports to be as accurate as `@vitest/coverage-istanbul` reports.
+
+- Coverage ignore hints have updated. See [Coverage | Ignoring Code](/guide/coverage.html#ignoring-code).
+- `coverage.ignoreEmptyLines` is removed. Lines without runtime code are no longer included in reports.
+- `coverage.experimentalAstAwareRemapping` is removed. This option is now enabled by default, and is the only supported remapping method.
+- `coverage.ignoreClassMethods` is now supported by V8 provider too.
+
 ### Removed options `coverage.all` and `coverage.extensions`
 
 In previous versions Vitest included all uncovered files in coverage report by default.

package.json

@@ -86,7 +86,6 @@
       "@sinonjs/[email protected]": "patches/@[email protected]",
       "[email protected]": "patches/[email protected]",
       "@types/[email protected]": "patches/@[email protected]",
-      "[email protected]": "patches/[email protected]",
       "[email protected]": "patches/[email protected]"
     },
     "onlyBuiltDependencies": [

packages/coverage-v8/package.json

@@ -75,7 +75,6 @@
     "@types/istanbul-reports": "catalog:",
     "@vitest/browser": "workspace:*",
     "pathe": "catalog:",
-    "v8-to-istanbul": "^9.3.0",
     "vite-node": "workspace:*",
     "vitest": "workspace:*"
   }