feat: display running processes, if vitest closes with timeout

docs/config/index.md

@@ -358,6 +358,7 @@ Custom reporters for output. Reporters can be [a Reporter instance](https://gith
   - `'junit'` - JUnit XML reporter (you can configure `testsuites` tag name with `VITEST_JUNIT_SUITE_NAME` environmental variable)
   - `'json'` -  give a simple JSON summary
   - `'html'` -  outputs HTML report based on [`@vitest/ui`](/guide/ui)
+  - `'hanging-process'` - displays a list of hanging processes, if Vitest cannot exit process safely. This might be a heavy operation, enable it only if Vitest consistently cannot exit process
   - path of a custom reporter (e.g. `'./path/to/reporter.ts'`, `'@scope/reporter'`)
 
 ### outputTruncateLength

packages/vitest/package.json

@@ -122,7 +122,8 @@
     "tinypool": "^0.3.0",
     "tinyspy": "^1.0.2",
     "vite": "^3.0.0 || ^4.0.0",
-    "vite-node": "workspace:*"
+    "vite-node": "workspace:*",
+    "why-is-node-running": "^2.2.2"
   },
   "devDependencies": {
     "@antfu/install-pkg": "^0.1.1",

packages/vitest/src/node/core.ts

@@ -548,8 +548,10 @@ export class Vitest {
    */
   async exit(force = false) {
     setTimeout(() => {
-      console.warn(`close timed out after ${this.config.teardownTimeout}ms`)
-      process.exit()
+      this.report('onProcessTimeout').then(() => {
+        console.warn(`close timed out after ${this.config.teardownTimeout}ms`)
+        process.exit()
+      })
     }, this.config.teardownTimeout).unref()
 
     await this.close()

packages/vitest/src/node/reporters/hanging-process.ts

@@ -0,0 +1,15 @@
+import { createRequire } from 'module'
+import type { Reporter } from '../../types'
+
+export class HangingProcessReporter implements Reporter {
+  whyRunning: (() => void) | undefined
+
+  onInit(): void {
+    const _require = createRequire(import.meta.url)
+    this.whyRunning = _require('why-is-node-running')
+  }
+
+  onProcessTimeout() {
+    this.whyRunning?.()
+  }
+}

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

@@ -5,6 +5,7 @@ import { VerboseReporter } from './verbose'
 import { TapReporter } from './tap'
 import { JUnitReporter } from './junit'
 import { TapFlatReporter } from './tap-flat'
+import { HangingProcessReporter } from './hanging-process'
 
 export { DefaultReporter }
 
@@ -16,6 +17,7 @@ export const ReportersMap = {
   'tap': TapReporter,
   'tap-flat': TapFlatReporter,
   'junit': JUnitReporter,
+  'hanging-process': HangingProcessReporter,
 }
 
 export type BuiltinReporters = keyof typeof ReportersMap

packages/vitest/src/types/reporter.ts

@@ -16,6 +16,8 @@ export interface Reporter {
   onServerRestart?: (reason?: string) => Awaitable<void>
 
   onUserConsoleLog?: (log: UserConsoleLog) => Awaitable<void>
+
+  onProcessTimeout?: () => Awaitable<void>
 }
 
 export type { Vitest }