From 1413382e1f2faa7dded070e0c67ef1ab936604cc Mon Sep 17 00:00:00 2001
From: DaveT1991 <129008657+DaveT1991@users.noreply.github.com>
Date: Fri, 10 Apr 2026 02:00:18 -0400
Subject: [PATCH] fix(coverage): descriptive error message when reports
 directory is removed during test run (#10117)
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Co-authored-by: Ari Perkkiö <ari.perkkio@gmail.com>
---
 packages/vitest/src/node/coverage.ts          | 22 +++++++++++++++++++
 .../test/temporary-files.unit.test.ts         | 19 ++++++++++++++++
 2 files changed, 41 insertions(+)
 create mode 100644 test/coverage-test/test/temporary-files.unit.test.ts

diff --git a/packages/vitest/src/node/coverage.ts b/packages/vitest/src/node/coverage.ts
index a8ecec1f3..131cf70b7 100644
--- a/packages/vitest/src/node/coverage.ts
+++ b/packages/vitest/src/node/coverage.ts
@@ -255,6 +255,22 @@ export class BaseCoverageProvider {
     this.pendingPromises = []
   }
 
+  private normalizeCoverageFileError(error: unknown): unknown {
+    if (
+      error instanceof Error
+      && 'code' in error
+      && error.code === 'ENOENT'
+      && !existsSync(this.coverageFilesDirectory)
+    ) {
+      return new Error(
+        `Something removed the coverage directory "${this.coverageFilesDirectory}" Vitest created earlier. Make sure you are not running multiple Vitests with the same "coverage.reportsDirectory" at the same time.`,
+        { cause: error },
+      )
+    }
+
+    return error
+  }
+
   onAfterSuiteRun({ coverage, environment, projectName, testFiles }: AfterSuiteRunMeta): void {
     if (!coverage) {
       return
@@ -278,6 +294,9 @@ export class BaseCoverageProvider {
     entry[environment][testFilenames] = filename
 
     const promise = fs.writeFile(filename, JSON.stringify(coverage), 'utf-8')
+      .catch((error) => {
+        throw this.normalizeCoverageFileError(error)
+      })
     this.pendingPromises.push(promise)
   }
 
@@ -307,6 +326,9 @@ export class BaseCoverageProvider {
 
           await Promise.all(chunk.map(async (filename) => {
             const contents = await fs.readFile(filename, 'utf-8')
+              .catch((error) => {
+                throw this.normalizeCoverageFileError(error)
+              })
             const coverage = JSON.parse(contents)
 
             onFileRead(coverage)
diff --git a/test/coverage-test/test/temporary-files.unit.test.ts b/test/coverage-test/test/temporary-files.unit.test.ts
new file mode 100644
index 000000000..c54fb2f2b
--- /dev/null
+++ b/test/coverage-test/test/temporary-files.unit.test.ts
@@ -0,0 +1,19 @@
+import { resolve } from 'node:path'
+import { expect, test } from 'vitest'
+import { BaseCoverageProvider } from 'vitest/node'
+
+test('missing coverage temp directory throws an actionable error', async () => {
+  const provider = new BaseCoverageProvider()
+  provider.coverageFilesDirectory = resolve('missing-coverage-directory', '.tmp')
+
+  provider.onAfterSuiteRun({
+    coverage: { '/src/math.ts': {} },
+    environment: 'ssr',
+    projectName: '',
+    testFiles: ['math.test.ts'],
+  } as any)
+
+  await expect(Promise.all(provider.pendingPromises)).rejects.toThrow(
+    `Something removed the coverage directory "${provider.coverageFilesDirectory}" Vitest created earlier. Make sure you are not running multiple Vitests with the same "coverage.reportsDirectory" at the same time.`,
+  )
+})
-- 
2.51.2