Build: [Warning] MaxListenersExceededWarning: Possible EventEmitter memory leak detected

[talves]

Describe the bug

As seen in this log at line time 3:16:09 PM:

(node:1262) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 data listeners added to [Socket]. Use emitter.setMaxListeners() to increase limit

Steps to reproduce

Running my infamous debug repo 😃

Expected behavior

Everything runs just fine. Wanted to give a heads up in the case this is not expected, so you can take a look at it.

Configuration

I did bump node from 10 to 12 to see if the warning was still there, just in case.

Screenshots

If applicable, add screenshots to help explain your problem.

[ehmicky]

Thanks for reporting @talves!

I can reproduce this issue: https://app.netlify.com/sites/stoic-payne-cbd2fe/deploys/5e5fb4be90ba688693b2d15d

Note that this only happens in the production CI, not when running the build locally (with Netlify CLI).

[talves]

@ehmicky I thought the CLI was not on this version locally (v2.36.0)

yarn why @netlify/build

[talves]

Let me install the latest version of the build and try it out.

[ehmicky]

@talves I can reproduce the bug even with the latest version.

If you regenerate the yarn.lock, you should get the latest @netlify/build (0.1.80 as I write this). @netlify/cli uses the following semver range: "@netlify/build": "^0.1.7". But your yarn.lock might hold this up.

[talves]

@ehmicky I was just removing it now and just confirmed it works local without the warning messages. 😁

Good catch on the yarn.lock, I would have gotten there, but not that fast. Thanks.

[ehmicky]

I am looking into this issue but debugging it is currently hard because of implementation details summarized in #878. Thanks for following up!

[erquhart]

Possibly related: https://github.com/netlify/cli/issues/717

[ehmicky]

Fixed in #949.

In a nutshell: we were not cleaning up some event listeners. This did have any impact except for a small memory leak and those logs being printed if a plugin had more than 10 event handlers (very unlikely in actual production code).

This was unfortunately not related to netlify/cli#717