[v25] --detectLeaks option always reports a leak when using jsdom environment

💥 Regression Report

Starting in v25, the --detectLeaks option will always report a leak when using env=jsdom.

Last working version

Worked up to version: v24.9.0

Stopped working in version: v25.0.0

To Reproduce

https://github.com/dylanwulf/jest-25-detect-leak npm run test: run test with jsdom environment npm run test:sixteen: run test with jest-environment-jsdom-sixteen npm run test:node: run test with node environment

When using jsdom or jest-environment-jsdom-sixteen it reports a memory leak even though the only thing in the test is a console log. When using the node environment, it does not report a leak.

Expected behavior

Should not report a memory leak for a simple test that clearly does not leak memory.

Link to repl or repo (highly encouraged)

https://github.com/dylanwulf/jest-25-detect-leak

Run npx envinfo --preset jest

Paste the results here:

  System:
    OS: Windows 10 10.0.18363
    CPU: (8) x64 Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
  Binaries:
    Node: 12.14.1 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.21.1 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
    npm: 6.13.4 - C:\Program Files\nodejs\npm.CMD
  npmPackages:
    jest: 25.1.0 => 25.1.0

[lh0x00]

I debugged and this issue from jsdom package, I will try to fix it and update in new version in Jest. Ref https://github.com/jsdom/jsdom/issues/2757

[SimenB]

Jest 26 is months away, and we’ll upgrade, not downgrade. So no need for a PR yet 🙂

If you want the old version of jsdom back, you can install jest-environment-jsdom@24 and use that through config.