The inspector `process.on(SIGPROF)` warning is non-standard.

[Fishrock123]

• Version: master (as of yesterday?)
• Platform: macOS
• Subsystem: src

An internal project is generating this warning when run:

process.on(SIGPROF) is reserved while debugging

It was not immediately clear to me that this was indeed from node, since no (node:pid) prefix was attached.

The warning is emitted from here and was added in 84ad31f about a year ago (though I'm not sure inspector was on by default then). My understanding is that this warning does not happen for us on LTS versions of Node.

Edit: We are not launching the inspector in any way when running into this.

[Fishrock123]

--trace-warnings also does not work to find where this warning is originating from, although I suspect it was from one of those "ensure this callback is run on any exit" modules.

[cjihrig]

I don't think it shows up as an official warning because it's just a print statement. I think it would have to use ProcessEmitWarning().

[Fishrock123]

Refs: #12709 (the above commit(s))

[Trott]

What should we do about this? Nothing? Change it to emit a warning? Something else?

[cjihrig]

This is a proper warning since #12709. The only question is whether or not the inspector should reserve SIGPROF, even when it's not in use. This check is always true if the inspector is started, which is different from active (HasConnectedSessions()).

[jasnell]

Given that it's now a proper warning, I think we should close this issue. Whether inspector should reserve SIGPROF is a separate concern.