fix(coverage): esbuild to preserve legal comments for ignore hints (#2496)

Author: AriPerkkio

packages/vitest/src/node/plugins/index.ts

@@ -92,6 +92,9 @@ export async function VitestPlugin(options: UserConfig = {}, ctx = new Vitest('t
  const config: ViteConfig = {
  esbuild: {
  sourcemap: 'external',
+
+ // Enables using ignore hint for coverage providers with @preserve keyword
+ legalComments: 'inline',
  },
  resolve: {
  // by default Vite resolves `module` field, which not always a native ESM module

test/coverage-test/coverage-report-tests/__snapshots__/c8.report.test.ts.snap

@@ -2272,6 +2272,8 @@ exports[`c8 json report 1`] = `
  "f": {
  "0": 1,
  "1": 1,
+ "10": 0,
+ "11": 0,
  "2": 2,
  "3": 2,
  "4": 0,
@@ -2330,6 +2332,54 @@ exports[`c8 json report 1`] = `
  },
  "name": "get",
  },
+ "10": {
+ "decl": {
+ "end": {
+ "column": 1,
+ "line": 29,
+ },
+ "start": {
+ "column": 7,
+ "line": 27,
+ },
+ },
+ "line": 27,
+ "loc": {
+ "end": {
+ "column": 1,
+ "line": 29,
+ },
+ "start": {
+ "column": 7,
+ "line": 27,
+ },
+ },
+ "name": "ignoredFunction",
+ },
+ "11": {
+ "decl": {
+ "end": {
+ "column": 1,
+ "line": 29,
+ },
+ "start": {
+ "column": 0,
+ "line": 29,
+ },
+ },
+ "line": 29,
+ "loc": {
+ "end": {
+ "column": 1,
+ "line": 29,
+ },
+ "start": {
+ "column": 0,
+ "line": 29,
+ },
+ },
+ "name": "get",
+ },
  "2": {
  "decl": {
  "end": {
@@ -2542,6 +2592,11 @@ exports[`c8 json report 1`] = `
  "21": 0,
  "22": 0,
  "23": 0,
+ "24": 1,
+ "25": 1,
+ "26": 1,
+ "27": 0,
+ "28": 0,
  "3": 1,
  "4": 1,
  "5": 2,
@@ -2721,6 +2776,56 @@ exports[`c8 json report 1`] = `
  "line": 24,
  },
  },
+ "24": {
+ "end": {
+ "column": 0,
+ "line": 25,
+ },
+ "start": {
+ "column": 0,
+ "line": 25,
+ },
+ },
+ "25": {
+ "end": {
+ "column": 39,
+ "line": 26,
+ },
+ "start": {
+ "column": 0,
+ "line": 26,
+ },
+ },
+ "26": {
+ "end": {
+ "column": 35,
+ "line": 27,
+ },
+ "start": {
+ "column": 0,
+ "line": 27,
+ },
+ },
+ "27": {
+ "end": {
+ "column": 59,
+ "line": 28,
+ },
+ "start": {
+ "column": 0,
+ "line": 28,
+ },
+ },
+ "28": {
+ "end": {
+ "column": 1,
+ "line": 29,
+ },
+ "start": {
+ "column": 0,
+ "line": 29,
+ },
+ },
  "3": {
  "end": {
  "column": 0,

test/coverage-test/coverage-report-tests/istanbul.report.test.ts

@@ -21,3 +21,19 @@ test('implicit else is included in branch count', async () => {
  expect(fileCoverage.b).toHaveProperty('0')
  expect(fileCoverage.b['0']).toHaveLength(2)
 })
+
+test('ignored code is excluded from the report', async () => {
+ const functionName = 'ignoredFunction'
+ const filename = '<process-cwd>/src/utils.ts'
+
+ const coverageMap = await readCoverageJson()
+ const fileCoverage = coverageMap[filename]
+
+ // Function should not be included in report
+ const functionCoverage = Object.values(fileCoverage.fnMap).find(fn => fn.name === functionName)
+ expect(functionCoverage).toBe(undefined)
+
+ // Function should still be found from the actual sources
+ const utils = await import('../src/utils')
+ expect(utils[functionName]).toBeTypeOf('function')
+})

test/coverage-test/coverage-report-tests/utils.ts

@@ -5,6 +5,7 @@ interface CoverageFinalJson {
  [filename: string]: {
  path: string
  b: Record<string, number[]>
+ fnMap: Record<string, { name: string }>
  // ... and more unrelated keys
  }
  }

test/coverage-test/src/utils.ts

@@ -22,3 +22,8 @@ export function run() {
  // this should not be covered
  divide(1, 1)
 }
+
+/* istanbul ignore next -- @preserve */
+export function ignoredFunction() {
+ return 'This function is excluded from istanbul coverage'
+}