fix(coverage): istanbul provider to work with JSDOM and process.env…

… usage

packages/coverage-istanbul/src/provider.ts

@@ -1,11 +1,12 @@
 import { existsSync, promises as fs } from 'node:fs'
 import { resolve } from 'pathe'
 import type { AfterSuiteRunMeta, CoverageIstanbulOptions, CoverageProvider, ReportContext, ResolvedCoverageOptions, Vitest } from 'vitest'
+import type { RawSourceMap } from 'vite-node'
 import { coverageConfigDefaults, defaultExclude, defaultInclude } from 'vitest/config'
 import { BaseCoverageProvider } from 'vitest/coverage'
 import libReport from 'istanbul-lib-report'
 import reports from 'istanbul-reports'
-import type { CoverageMap } from 'istanbul-lib-coverage'
+import type { CoverageMap, CoverageMapData } from 'istanbul-lib-coverage'
 import libCoverage from 'istanbul-lib-coverage'
 import libSourceMaps from 'istanbul-lib-source-maps'
 import { type Instrumenter, createInstrumenter } from 'istanbul-lib-instrument'
@@ -15,6 +16,7 @@ import _TestExclude from 'test-exclude'
 import { COVERAGE_STORE_KEY } from './constants'
 
 type Options = ResolvedCoverageOptions<'istanbul'>
+type CoverageResult = CoverageMapData & { [key: string]: { inputSourceMap?: RawSourceMap } }
 
 interface TestExclude {
   new(opts: {
@@ -43,7 +45,7 @@ export class IstanbulCoverageProvider extends BaseCoverageProvider implements Co
    * If storing in memory causes issues, we can simply write these into fs in `onAfterSuiteRun`
    * and read them back when merging coverage objects in `onAfterAllFilesRun`.
    */
-  coverages: any[] = []
+  coverages: CoverageResult[] = []
 
   initialize(ctx: Vitest) {
     const config: CoverageIstanbulOptions = ctx.config.coverage
@@ -93,14 +95,17 @@ export class IstanbulCoverageProvider extends BaseCoverageProvider implements Co
     const sourceMap = pluginCtx.getCombinedSourcemap()
     sourceMap.sources = sourceMap.sources.map(removeQueryParameters)
 
-    const code = this.instrumenter.instrumentSync(sourceCode, id, sourceMap as any)
+    const code = this.instrumenter.instrumentSync(sourceCode, id, sourceMap)
     const map = this.instrumenter.lastSourceMap() as any
 
-    return { code, map }
+    return {
+      code: prepareInputSourceMapForViteTransforms(code),
+      map,
+    }
   }
 
   onAfterSuiteRun({ coverage }: AfterSuiteRunMeta) {
-    this.coverages.push(coverage)
+    this.coverages.push(coverage as CoverageResult)
   }
 
   async clean(clean = true) {
@@ -121,6 +126,7 @@ export class IstanbulCoverageProvider extends BaseCoverageProvider implements Co
       await this.includeUntestedFiles(mergedCoverage)
 
     includeImplicitElseBranches(mergedCoverage)
+    revertViteTransformRewrites(mergedCoverage)
 
     const sourceMapStore = libSourceMaps.createSourceMapStore()
     const coverageMap: CoverageMap = await sourceMapStore.transformCoverage(mergedCoverage)
@@ -251,3 +257,40 @@ function isEmptyCoverageRange(range: libCoverage.Range) {
     || range.end.column === undefined
   )
 }
+
+/**
+ * Instrumentation adds source map into the JS code. It contains source code in
+ * `sourcesContent` field. Vite transform is producing invalid syntax when
+ * `process.env` is present in `sourcesContent` string. As work-around we'll
+ * replace `process.env` before Vite transforms and revert it back after
+ * remapping the coverage.
+ */
+function prepareInputSourceMapForViteTransforms(code: string) {
+  if (code.includes('process.env')) {
+    return code.split('\n').map((line) => {
+      // Inline source map contains "sourcesContent" field which contains source code on a single line
+      if (line.includes('sourcesContent: ["'))
+        return line.replace(/process\.env/g, 'VITEST_PROCESS_ENV')
+
+      return line
+    }).join('\n')
+  }
+
+  return code
+}
+
+function revertViteTransformRewrites(coverageMap: CoverageMap) {
+  for (const file of coverageMap.files()) {
+    const { data } = coverageMap.fileCoverageFor(file) as { data: CoverageResult[string] }
+
+    if (data.inputSourceMap?.sourcesContent) {
+      data.inputSourceMap.sourcesContent = data.inputSourceMap.sourcesContent.map((code) => {
+        // Restore rewrites back to original ones
+        if (code.includes('VITEST_PROCESS_ENV'))
+          return code.replace(/VITEST_PROCESS_ENV/g, 'process.env')
+
+        return code
+      })
+    }
+  }
+}

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

@@ -23,6 +23,7 @@ exports[`custom json report 1`] = `
     "<process-cwd>/src/importEnv.ts",
     "<process-cwd>/src/index.mts",
     "<process-cwd>/src/multi-suite.ts",
+    "<process-cwd>/src/process-env.ts",
     "<process-cwd>/src/utils.ts",
   ],
 }

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

@@ -1425,6 +1425,54 @@ exports[`istanbul json report 1`] = `
       },
     },
   },
+  "<process-cwd>/src/process-env.ts": {
+    "b": {},
+    "branchMap": {},
+    "f": {
+      "0": 1,
+    },
+    "fnMap": {
+      "0": {
+        "decl": {
+          "end": {
+            "column": 29,
+            "line": 1,
+          },
+          "start": {
+            "column": 16,
+            "line": 1,
+          },
+        },
+        "loc": {
+          "end": {
+            "column": null,
+            "line": 3,
+          },
+          "start": {
+            "column": 29,
+            "line": 1,
+          },
+        },
+        "name": "getNodeEnv",
+      },
+    },
+    "path": "<process-cwd>/src/process-env.ts",
+    "s": {
+      "0": 1,
+    },
+    "statementMap": {
+      "0": {
+        "end": {
+          "column": null,
+          "line": 2,
+        },
+        "start": {
+          "column": 2,
+          "line": 2,
+        },
+      },
+    },
+  },
   "<process-cwd>/src/untested-file.ts": {
     "b": {
       "0": [

test/coverage-test/coverage-report-tests/__snapshots__/v8.report.test.ts.snap

@@ -3528,6 +3528,109 @@ exports[`v8 json report 1`] = `
       },
     },
   },
+  "<process-cwd>/src/process-env.ts": {
+    "all": false,
+    "b": {
+      "0": [
+        1,
+      ],
+    },
+    "branchMap": {
+      "0": {
+        "line": 1,
+        "loc": {
+          "end": {
+            "column": 1,
+            "line": 3,
+          },
+          "start": {
+            "column": 7,
+            "line": 1,
+          },
+        },
+        "locations": [
+          {
+            "end": {
+              "column": 1,
+              "line": 3,
+            },
+            "start": {
+              "column": 7,
+              "line": 1,
+            },
+          },
+        ],
+        "type": "branch",
+      },
+    },
+    "f": {
+      "0": 1,
+    },
+    "fnMap": {
+      "0": {
+        "decl": {
+          "end": {
+            "column": 1,
+            "line": 3,
+          },
+          "start": {
+            "column": 7,
+            "line": 1,
+          },
+        },
+        "line": 1,
+        "loc": {
+          "end": {
+            "column": 1,
+            "line": 3,
+          },
+          "start": {
+            "column": 7,
+            "line": 1,
+          },
+        },
+        "name": "getNodeEnv",
+      },
+    },
+    "path": "<process-cwd>/src/process-env.ts",
+    "s": {
+      "0": 1,
+      "1": 1,
+      "2": 1,
+    },
+    "statementMap": {
+      "0": {
+        "end": {
+          "column": 30,
+          "line": 1,
+        },
+        "start": {
+          "column": 0,
+          "line": 1,
+        },
+      },
+      "1": {
+        "end": {
+          "column": 29,
+          "line": 2,
+        },
+        "start": {
+          "column": 0,
+          "line": 2,
+        },
+      },
+      "2": {
+        "end": {
+          "column": 1,
+          "line": 3,
+        },
+        "start": {
+          "column": 0,
+          "line": 3,
+        },
+      },
+    },
+  },
   "<process-cwd>/src/untested-file.ts": {
     "all": true,
     "b": {

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

@@ -2,6 +2,8 @@
  * Istanbul coverage provider specific test cases
  */
 
+import { resolve } from 'node:path'
+import { readFileSync } from 'node:fs'
 import { expect, test } from 'vitest'
 import { readCoverageJson } from './utils'
 
@@ -50,3 +52,14 @@ test('tests with multiple suites are covered', async () => {
     1: 1,
   })
 })
+
+test('vite transforms should not show on coverage report', async () => {
+  const filePath = resolve('./coverage/src/process-env.ts.html')
+  const htmlContent = readFileSync(filePath, 'utf-8')
+
+  // Pattern used to replace `process.env` - should not end up in coverage report
+  expect(htmlContent).not.toContain('VITEST_PROCESS_ENV')
+
+  // Actual source code
+  expect(htmlContent).toContain('process.env.NODE_ENV')
+})

test/coverage-test/src/process-env.ts

@@ -0,0 +1,3 @@
+export function getNodeEnv() {
+  return process.env.NODE_ENV
+}

test/coverage-test/test/jsdom.test.ts

@@ -0,0 +1,8 @@
+// @vitest-environment jsdom
+
+import { expect, test } from 'vitest'
+import { getNodeEnv } from '../src/process-env'
+
+test('process.env works', () => {
+  expect(getNodeEnv()).toBe('test')
+})