[Tracking Requested - why for this release]: too many unexpected temp file created in temp folder.

Steps to reproduce:

1. Help > About Nightly
   --- Automatically start check for update as expected
2. Quit Nightly

Actual results:
Many many MozillaBackgroundTask-xxxxxxxx-pingsender-x are created in the temp folder.

Expected Results:
Such files should not be left. Should be removed from temp file.

Regression window:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=8ad4b1bf184499ef0550b1014f6e7326ed132750&tochange=c0e719d876173a56b16e89b64ef3eb536f352467

Reopen.
I think this is different from bug 1722777, because the bug appears since m-c build id 0211016214337.

(In reply to Alice0775 White from comment #3)

Reopen.
I think this is different from bug 1722777, because the bug appears since m-c build id 0211016214337.

As Nick indicated in bug 1722777 comment 7: we were previously using the background task machinery just for the background updater, and now we're using it for pingsender as well. So the behavior is showing up in more situations.

(In reply to Alice0775 White from comment #0)

Many many MozillaBackgroundTask-xxxxxxxx-pingsender-x are created in the temp folder.

"Many many" is concerning. My understanding is that these are temporary profiles used for the background task. And so one invocation of the background task should result in at most one temporary profile (Nick, do I have that right?). And in theory, we should be invoking the pingsender background task at most once on shutdown.

Alice, can you confirm that there are indeed multiple temporary folders showing up for a single restart? How many?

3 or 4 files / 1 quit with new profile. --- 3 or 4 files now
another +3 or +2 files / 1 next quit. --- 6 files now
another +3 files / 1 next quit. --- 9 files now
another +3 files / 1 next quit. --- 12 files now
...
...
There seems to be no limit to the number of files.

Does this reproduce since bug 1736373 reverted back to pingsender1?

(In reply to Ryan VanderMeulen [:RyanVM] from comment #6)

Does this reproduce since bug 1736373 reverted back to pingsender1?

It's an artifact from the background task machinery, so I assume it would not. Ideally I'd still use this bug to track and address the issue for pingsender 2 so that we can get it turned back on.

[Tracking Requested - why for this release]:

No longer reproduce the issue in Nightly95.0a1(20211026090355) Windows10.

Sorry, didn't see comment 7 before adding my NI.

This is a duplicate of Bug 1722777, which has been addressed. \o/