fix(coverage): invalidate circular modules correctly on rerun with coverage

packages/coverage-istanbul/src/provider.ts

@@ -239,6 +239,7 @@ export class IstanbulCoverageProvider extends BaseCoverageProvider<ResolvedCover
     if (node.id && !this.transformedModuleIds.has(node.id)) {
       moduleGraph.invalidateModule(node, seen)
     }
+    seen.add(node) // to avoid infinite loops in circular dependencies
     node.importedModules.forEach((mod) => {
       this.invalidateTree(mod, moduleGraph, seen)
     })

test/coverage-test/fixtures/src/circularA.ts

@@ -0,0 +1,7 @@
+import { circularB } from './circularB'
+
+export const CalledB: number[] = []
+
+export function circularA() {
+  return circularB()
+}

test/coverage-test/fixtures/src/circularB.ts

@@ -0,0 +1,5 @@
+import { CalledB } from './circularA'
+
+export function circularB() {
+  return CalledB.push(CalledB.length)
+}

test/coverage-test/fixtures/test/circular.test.ts

@@ -0,0 +1,15 @@
+import { expect, it } from 'vitest'
+import { CalledB, circularA } from '../src/circularA'
+
+it('circular', () => {
+  CalledB.length = 0
+
+  circularA()
+
+  expect(CalledB.length).toBe(1)
+
+  circularA()
+  circularA()
+
+  expect(CalledB).toEqual([0, 1, 2])
+})

test/coverage-test/test/run-dynamic-coverage.test.ts

@@ -26,6 +26,39 @@ test('enableCoverage() collects coverage after being called', async () => {
   expect(coverageMap.files()).toContain('<process-cwd>/fixtures/src/math.ts')
 })
 
+test('enableCoverage() invalidates circular modules', async () => {
+  await cleanupCoverageJson()
+
+  await expect(readCoverageMap(), 'coverage map should not be on the disk').rejects.toThrowError(/no such file/)
+
+  // Simulating user actions in the VSCode Vitest extension:
+  // 1. User clicks "Run Test with Coverage" to generate coverage files normally
+  const { ctx } = await runVitest({
+    include: ['fixtures/test/circular.test.ts'],
+    watch: false,
+    coverage: {
+      enabled: true,
+      reporter: 'json',
+    },
+  })
+
+  const coverageMap = await readCoverageMap()
+  expect(coverageMap.files()).toEqual([
+    '<process-cwd>/fixtures/src/circularA.ts',
+    '<process-cwd>/fixtures/src/circularB.ts',
+  ])
+
+  // 2. User reruns tests with coverage
+  await ctx!.enableCoverage()
+  await ctx!.rerunFiles()
+
+  const coverageMap2 = await readCoverageMap()
+  expect(coverageMap2.files()).toEqual([
+    '<process-cwd>/fixtures/src/circularA.ts',
+    '<process-cwd>/fixtures/src/circularB.ts',
+  ])
+})
+
 test('disableCoverage() stops collecting coverage going forward', async () => {
   const { ctx } = await runVitest({
     include: ['fixtures/test/math.test.ts'],