1959966 - Firefox fails to relaunch immediately after being quit via App menu or Ctrl+Shift+Q with warning dialog active

Status: VERIFIED FIXED

(Firefox :: Data Loss Prevention, defect)

Description

[Bianca Hidecuti, Desktop Test Engineering [:bhidecuti]]

Attachment: video showing the issue

Found in

• 138.0b5

Affected versions

• 139.0a1 (2025-04-10)
• 138.0b5

Tested platforms

• Affected platforms: Windows 10/11
• Unaffected platforms: Ubuntu, macOS

Preconditions

• Download the DLP test assets from https://drive.google.com/file/d/1yjqVRuxdKV3WnO7D2wzMgDXBuYBxUgVw/view
• Create a distribution folder inside the Firefox folder and paste the policies-1.json to it and then rename it to policies.json
• DLP Agent is running: .\content_analysis_sdk_agent.exe --user --toblock=.*\d{3}-?\d{2}-?\d{4}.* --towarn=.*warn.* --delays=10

Steps to reproduce

1. Navigate to any website (e.g. https://support.mozilla.org/)
2. Paste the "warning text" into the search field
3. Wait for the “This content may be unsafe” dialog to appear, then quit the browser using the Application menu or Ctrl+Shift+Q keys
4. Relaunch Firefox and observe the behavior

Expected result

• Firefox should launch immediately

Actual result

• Firefox does not launch for approximately a minute

Regression range

• Mozregression points to bug 1957902

Additional notes

• Attached a screen recording
• Also reproducing when restarting the browser
• After quitting, Firefox remains active as a background process for about a minute (can be checked in Task Manager). Ending the process allows immediate relaunch
• Not reproducing when closing Firefox via the window Close button ("X")

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

:gstoll, since you are the author of the regressor, bug 1957902, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 2

[Greg Stoll :gstoll]

The regressor was just fixing the quit dialog, so I suspect this has been going on for longer. (although looking a little more closely I did do some refactoring there, so maybe I did break it!)

Comment 3

[Greg Stoll :gstoll]

Attachment: Bug 1959966 - cancel WARN Content Analysis dialogs when quitting to avoid a shutdownhang r=#dlp-reviewers!

Explicitly cancel pending WARNs when we quit so that the dialogs go away
and nothing gets stuck. I feel like this used to work by coincidence,
but now we do it explicitly.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1191b21ec8f0
cancel WARN Content Analysis dialogs when quitting to avoid a shutdownhang r=dlp-reviewers,handyman

Comment 5

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/1191b21ec8f0

Comment 6

[Bianca Hidecuti, Desktop Test Engineering [:bhidecuti]]

Attachment: 1959966.mp4

Verified this using Firefox Nightly 139.0a1 (2025-04-13), on Windows 10 and 11 and the issue is still reproducing as described in Comment 0. Firefox does not launch for approximately a minute after being quit via App menu or Ctrl+Shift+Q with warning dialog active.
Reopening the ticket.

Comment 7

[Greg Stoll :gstoll]

Sigh, this works when you close the window with the top-right button in the toolbar, but not when selecting Quit from the hamburger menu. (as :bhidecuti showed in the video) I'll take a look.

Comment 8

[Greg Stoll :gstoll]

Attachment: Bug 1959966 - cancel WARN Content Analysis dialogs in an earlier event when quitting to avoid a shutdownhang r=#dlp-reviewers!

Per the comment, the quit-application event can be delayed if the user
quits via keyboard or the hamburger menu (as opposed to simply closing
the last window). I didn't dig too deep into this but this seems like
the kind of thing we can do in quit-application-granted anyway.

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a37d22ff53f5
cancel WARN Content Analysis dialogs in an earlier event when quitting to avoid a shutdownhang r=dlp-reviewers,handyman

Comment 10

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/a37d22ff53f5

Comment 11

[BugBot [:suhaib / :marco/ :calixte]]

The patch landed in nightly and beta is affected.
:gstoll, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
  • See https://wiki.mozilla.org/Release_Management/Requesting_an_Uplift for documentation on how to request an uplift.
• If no, please set status-firefox138 to wontfix.

For more information, please visit BugBot documentation.

Comment 12

[Greg Stoll :gstoll]

Since this only affects WARN dialogs, not going to uplift.

Comment 13

[Bianca Hidecuti, Desktop Test Engineering [:bhidecuti]]

Verified as fixed using Firefox Nightly 139.0a1 (2025-04-17), on Windows 11. Firefox now relaunches immediately after being quit via App menu or Ctrl+Shift+Q with warning dialog active.