From 4cae680039e13c873848ac5076c8c8a91c6720f0 Mon Sep 17 00:00:00 2001
From: Rob Brackett <rob@robbrackett.com>
Date: Fri, 28 May 2021 05:49:27 -0700
Subject: [PATCH] Ignore DNSCHANNEL when using --detectOpenHandles (#11470)

---
 CHANGELOG.md                                       |  1 +
 .../__snapshots__/detectOpenHandles.ts.snap        |  2 +-
 .../jest-core/src/__tests__/collectHandles.test.js | 14 ++++++++++++++
 packages/jest-core/src/collectHandles.ts           |  6 +++++-
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 36888f1eb302..ef1541b09591 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@
 ### Fixes
 
 - `[jest-circus, @jest/test-sequencer]` Remove dependency on `jest-runner` ([#11466](https://github.com/facebook/jest/pull/11466))
+- `[jest-core]` Do not warn about `DNSCHANNEL` handles when using the `--detectOpenHandles` option ([#11470](https://github.com/facebook/jest/pull/11470))
 - `[jest-runner]` Remove dependency on `jest-config` ([#11466](https://github.com/facebook/jest/pull/11466))
 - `[jest-worker]` Loosen engine requirement to `>= 10.13.0` ([#11451](https://github.com/facebook/jest/pull/11451))
 
diff --git a/e2e/__tests__/__snapshots__/detectOpenHandles.ts.snap b/e2e/__tests__/__snapshots__/detectOpenHandles.ts.snap
index 40aeef9d4529..42094ed3b596 100644
--- a/e2e/__tests__/__snapshots__/detectOpenHandles.ts.snap
+++ b/e2e/__tests__/__snapshots__/detectOpenHandles.ts.snap
@@ -13,7 +13,7 @@ This usually means that there are asynchronous operations that weren't stopped i
 exports[`prints out info about open handlers 1`] = `
 Jest has detected the following 1 open handle potentially keeping Jest from exiting:
 
-  ●  DNSCHANNEL
+  ●  TCPSERVERWRAP
 
       12 | const app = new Server();
       13 |
diff --git a/packages/jest-core/src/__tests__/collectHandles.test.js b/packages/jest-core/src/__tests__/collectHandles.test.js
index 9e97b8c64498..e35201822189 100644
--- a/packages/jest-core/src/__tests__/collectHandles.test.js
+++ b/packages/jest-core/src/__tests__/collectHandles.test.js
@@ -6,6 +6,7 @@
  *
  */
 
+import {promises as dns} from 'dns';
 import http from 'http';
 import {PerformanceObserver} from 'perf_hooks';
 import collectHandles from '../collectHandles';
@@ -38,6 +39,19 @@ describe('collectHandles', () => {
     obs.disconnect();
   });
 
+  it('should not collect the DNSCHANNEL open handle', async () => {
+    const handleCollector = collectHandles();
+
+    const resolver = new dns.Resolver();
+    resolver.getServers();
+
+    const openHandles = await handleCollector();
+
+    expect(openHandles).not.toContainEqual(
+      expect.objectContaining({message: 'DNSCHANNEL'}),
+    );
+  });
+
   it('should collect handles opened in test functions with `done` callbacks', done => {
     const handleCollector = collectHandles();
     const server = http.createServer((_, response) => response.end('ok'));
diff --git a/packages/jest-core/src/collectHandles.ts b/packages/jest-core/src/collectHandles.ts
index c98543d647c1..6212625a8914 100644
--- a/packages/jest-core/src/collectHandles.ts
+++ b/packages/jest-core/src/collectHandles.ts
@@ -62,12 +62,16 @@ export default function collectHandles(): HandleCollectionResult {
       triggerAsyncId,
       resource: {} | NodeJS.Timeout,
     ) {
+      // Skip resources that should not generally prevent the process from
+      // exiting, not last a meaningfully long time, or otherwise shouldn't be
+      // tracked.
       if (
         type === 'PROMISE' ||
         type === 'TIMERWRAP' ||
         type === 'ELDHISTOGRAM' ||
         type === 'PerformanceObserver' ||
-        type === 'RANDOMBYTESREQUEST'
+        type === 'RANDOMBYTESREQUEST' ||
+        type === 'DNSCHANNEL'
       ) {
         return;
       }