fix(coverage): warn if vitest and @vitest/* versions don't match

packages/coverage-istanbul/src/provider.ts

@@ -26,11 +26,12 @@ import type { CoverageMap } 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'
-// @ts-expect-error @istanbuljs/schema has no type definitions
+// @ts-expect-error missing types
 import { defaults as istanbulDefaults } from '@istanbuljs/schema'
-
 // @ts-expect-error missing types
 import _TestExclude from 'test-exclude'
+
+import { version } from '../package.json' with { type: 'json' }
 import { COVERAGE_STORE_KEY } from './constants'
 
 type Options = ResolvedCoverageOptions<'istanbul'>
@@ -76,6 +77,16 @@ export class IstanbulCoverageProvider extends BaseCoverageProvider implements Co
   initialize(ctx: Vitest): void {
     const config: CoverageIstanbulOptions = ctx.config.coverage
 
+    if (ctx.version !== version) {
+      ctx.logger.warn(
+        c.yellow(
+          `Loaded ${c.inverse(c.yellow(` vitest@${ctx.version} `))} and ${c.inverse(c.yellow(` @vitest/coverage-istanbul@${version} `))}.`
+          + '\nRunning mixed versions is not supported and may lead into bugs'
+          + '\nUpdate your dependencies and make sure the versions match.',
+        ),
+      )
+    }
+
     this.ctx = ctx
     this.options = {
       ...coverageConfigDefaults,

packages/coverage-v8/src/provider.ts

@@ -34,10 +34,11 @@ import type {
   ResolvedCoverageOptions,
 } from 'vitest'
 import type { Vitest } from 'vitest/node'
-
 // @ts-expect-error missing types
 import _TestExclude from 'test-exclude'
 
+import { version } from '../package.json' with { type: 'json' }
+
 interface TestExclude {
   new (opts: {
     cwd?: string | string[]
@@ -91,6 +92,16 @@ export class V8CoverageProvider extends BaseCoverageProvider implements Coverage
   initialize(ctx: Vitest): void {
     const config: CoverageV8Options = ctx.config.coverage
 
+    if (ctx.version !== version) {
+      ctx.logger.warn(
+        c.yellow(
+          `Loaded ${c.inverse(c.yellow(` vitest@${ctx.version} `))} and ${c.inverse(c.yellow(` @vitest/coverage-v8@${version} `))}.`
+          + '\nRunning mixed versions is not supported and may lead into bugs'
+          + '\nUpdate your dependencies and make sure the versions match.',
+        ),
+      )
+    }
+
     this.ctx = ctx
     this.options = {
       ...coverageConfigDefaults,

test/coverage-test/package.json

@@ -3,7 +3,8 @@
   "type": "module",
   "private": true,
   "scripts": {
-    "test": "vitest --workspace=vitest.workspace.custom.ts"
+    "test": "vitest --workspace=vitest.workspace.custom.ts",
+    "vitest": "vitest"
   },
   "devDependencies": {
     "@ampproject/remapping": "^2.2.1",
@@ -19,6 +20,7 @@
     "istanbul-lib-report": "^3.0.1",
     "magic-string": "^0.30.10",
     "magicast": "^0.3.3",
+    "strip-ansi": "^7.1.0",
     "unplugin-swc": "^1.4.4",
     "vite": "latest",
     "vitest": "workspace:*",

test/coverage-test/test/mixed-versions-warning.unit.test.ts

@@ -0,0 +1,50 @@
+import { expect, test, vi } from 'vitest'
+import { configDefaults } from 'vitest/config'
+import V8Provider from '@vitest/coverage-v8'
+import packageJson from '@vitest/coverage-v8/package.json'
+import IstanbulProvider from '@vitest/coverage-istanbul'
+import stripAnsi from 'strip-ansi'
+
+const version = packageJson.version
+
+test('v8 provider logs warning if versions do not match', async () => {
+  const provider = await V8Provider.getProvider()
+  const warn = vi.fn()
+
+  provider.initialize({
+    version: '1.0.0',
+    logger: { warn },
+    config: configDefaults,
+  } as any)
+
+  expect(warn).toHaveBeenCalled()
+
+  const message = warn.mock.calls[0][0]
+
+  expect(stripAnsi(message)).toMatchInlineSnapshot(`
+    "Loaded  [email protected]  and  @vitest/coverage-v8@${version} .
+    Running mixed versions is not supported and may lead into bugs
+    Update your dependencies and make sure the versions match."
+  `)
+})
+
+test('istanbul provider logs warning if versions do not match', async () => {
+  const provider = await IstanbulProvider.getProvider()
+  const warn = vi.fn()
+
+  provider.initialize({
+    version: '1.0.0',
+    logger: { warn },
+    config: configDefaults,
+  } as any)
+
+  expect(warn).toHaveBeenCalled()
+
+  const message = warn.mock.calls[0][0]
+
+  expect(stripAnsi(message)).toMatchInlineSnapshot(`
+    "Loaded  [email protected]  and  @vitest/coverage-istanbul@${version} .
+    Running mixed versions is not supported and may lead into bugs
+    Update your dependencies and make sure the versions match."
+  `)
+})