From 4ea625d76fd2de31f69a35b02964d4267541a1cf Mon Sep 17 00:00:00 2001
From: Oliver Salzburg <oliver.salzburg@gmail.com>
Date: Tue, 2 Nov 2021 14:50:18 +0100
Subject: [PATCH] fix: Incorrect detection of open ZLIB handles

It appears that some calls into `zlib` are detected as incorrectly being open. This change ignores open handles in the ZLIB context.

Fixes #11542
---
 CHANGELOG.md                                      |  1 +
 .../src/__tests__/collectHandles.test.js          | 15 +++++++++++++++
 packages/jest-core/src/collectHandles.ts          |  3 ++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4fd5bcd972f8..d093394b71b5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 ### Fixes
 
 - `[expect]` Allow again `expect.Matchers` generic with single value ([#11986](https://github.com/facebook/jest/pull/11986))
+- `[jest-core]` Incorrect detection of open ZLIB handles ([#12022](https://github.com/facebook/jest/pull/12022))
 - `[jest-environment-jsdom]` Add `@types/jsdom` dependency ([#11999](https://github.com/facebook/jest/pull/11999))
 - `[jest-transform]` Improve error and warning messages ([#11998](https://github.com/facebook/jest/pull/11998))
 
diff --git a/packages/jest-core/src/__tests__/collectHandles.test.js b/packages/jest-core/src/__tests__/collectHandles.test.js
index e35201822189..b0628157af00 100644
--- a/packages/jest-core/src/__tests__/collectHandles.test.js
+++ b/packages/jest-core/src/__tests__/collectHandles.test.js
@@ -9,6 +9,7 @@
 import {promises as dns} from 'dns';
 import http from 'http';
 import {PerformanceObserver} from 'perf_hooks';
+import zlib from 'zlib';
 import collectHandles from '../collectHandles';
 
 describe('collectHandles', () => {
@@ -52,6 +53,20 @@ describe('collectHandles', () => {
     );
   });
 
+  it('should not collect the ZLIB open handle', async () => {
+    const handleCollector = collectHandles();
+
+    const decompressed = zlib.inflateRawSync(
+      Buffer.from('cb2a2d2e5128492d2ec9cc4b0700', 'hex'),
+    );
+
+    const openHandles = await handleCollector();
+
+    expect(openHandles).not.toContainEqual(
+      expect.objectContaining({message: 'ZLIB'}),
+    );
+  });
+
   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 6212625a8914..72fea6ee6b94 100644
--- a/packages/jest-core/src/collectHandles.ts
+++ b/packages/jest-core/src/collectHandles.ts
@@ -71,7 +71,8 @@ export default function collectHandles(): HandleCollectionResult {
         type === 'ELDHISTOGRAM' ||
         type === 'PerformanceObserver' ||
         type === 'RANDOMBYTESREQUEST' ||
-        type === 'DNSCHANNEL'
+        type === 'DNSCHANNEL' ||
+        type === 'ZLIB'
       ) {
         return;
       }