1586741 - Unable to open the browser toolbox, `uncaught exception: Object`

Status: RESOLVED INACTIVE

(DevTools :: Framework, defect, P2)

Description

[Itiel]

Attachment: about:support

Using Windows 10, latest Nightly.

I see this issue often when I build Firefox locally, where I open Firefox, hit Ctrl+Shift+Alt+I, I see a spinner and then nothing. No toolbox.

When this happens, I see the following error on the console:
uncaught exception: Object

After each time I see this I think that I must have messed the profile up, so I just ./mach clobber and start all over, but now I can also see this in a "normal" profile on Nightly.
I believe that what lead to this to happen is me opening the toolbox right after launching Nightly, restarting and repeating.

Things I've tried to fix it:

1. Restarting
2. Disabling session restore and restarting
3. Disabling "Enable browser chrome and add-on debugging toolboxes" and "Enable remote debugging", restarting Nightly and re-enabling
4. Trying from safe mode

but nothing. Obviously this will work on a new profile but that's not the point.

Errors from the console that could be related, when starting Nightly:

NS_ERROR_XPC_GS_RETURNED_FAILURE: ServiceManager::GetService returned failure code: UrlClassifierListManager.jsm:73
NS_ERROR_XPC_GS_RETURNED_FAILURE: ServiceManager::GetService returned failure code: SafeBrowsing.jsm:303
NS_ERROR_FAILURE: Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIInterfaceRequestor.getInterface] 2 network-response-listener.js:84

about:support output attached.

Comment 1

[Itiel]

This now happened to my main profile, after restarting Nightly multiple times in short interval with the toolbox open :(

Comment 2

[Itiel]

Also, if related, when I close the normal devtools I now get this error in the console:
about:devtools-toolbox : Unable to run script because scripts are blocked internally.

Comment 3

[Itiel]

This seems to go away after the next Nightly update, until it happens again when I restart Nightly frequently with the toolbox open.
Scratch that, I just updated Nightly and this persisted afterwards. Still unsure about the exact STR.

Comment 4

[Belén [:ladybenko]]

Hi Itiel, I'm afraid I'm not able to reproduce this.

• Is there a particular panel in the toolbox that you have open when you restart? Or does it happen regardless which panel is selected?
• Likewise, is there a particular website you're inspecting/debugging, or does it happen regardless that?
• Does it happen if you create a new profile with no extensions added?

Thanks for your help!

Comment 5

[Itiel]

(In reply to Belén [:ladybenko] from comment #4)

Hi Itiel, I'm afraid I'm not able to reproduce this.

• Is there a particular panel in the toolbox that you have open when you restart? Or does it happen regardless which panel is selected?
• Likewise, is there a particular website you're inspecting/debugging, or does it happen regardless that?
• Does it happen if you create a new profile with no extensions added?

Thanks for your help!

1. I'm not sure, but I think the Inspector most of the time. Though I don't think this matters.
2. Regardless.
3. Yes. Happened also on a firefox built locally.

Comment 6

[Alexandre Poirot [:ochameau]]

I did reproduced the same exception when a Nightly update was queued up.
The process we run to open the browser toolbox must be failing because of the update.
Firefox probably rejects running another instance when an update is queued.

It should be reproducible by using an archived version of Firefox:
https://archive.mozilla.org/pub/firefox/nightly/2019/10/

I would suggest to first try to improve the error message/exception so that we can more easily debug such issue or similar.
Itiel reports this exception when using a local build, where no updates should be happening.
So having a better error message would probably help figure out yet another issue.

Comment 7

[Jan Honza Odvarko [:Honza] (always need-info? me)]

Belén, it would be great to fix this problem. I am seeing two other reports related to the Browser Toolbox opening issues.

• Bug 1522798 - Browser Toolbox doesn't open in Windows 10 sometimes
• Bug 1615412 - Periodically unable to connect Browser Toolbox, despite numerous process restarts, or toolbox split with error message shown on the left

Honza

Comment 8

[Alexandre Poirot [:ochameau]]

In this bug I would suggest only trying to improve the logs in order to help understanding why the browser toolbox fails opening.

Otherwise there is two confirmed known issues:

• pending updates, bug 1120863, where there is a suggestion on how to fix it, but this requires modifying c++.
• IPv6 issue, bug 1615412, which seems to be specific to MacOS.

Comment 9

[Jaakko Hannikainen]

Tldr: remove chrome_debugger_profile/prefs.js from your profile folder if you hit this bug.

Hi! I hit this one and managed to track down the intermediate cause: Having a high number in "toolkit.startup.recent_crashes" in chrome_debugger_profile/prefs.js (seemingly recent_crashes >= max_resumed_crashes == 3) causes this bug. I could try fixing this, but I'm not exactly sure what would be the proper fix here.

I think I also saw the recent_crashes to increment if I closed down my browser window while having the toolkit open, but I couldn't reliably replicate that. I guess that's one half of the 'root' bug here.

Replication:

1. Open firefox, open browser toolbox and see that it works
2. in your profile folder: echo 'user_pref("toolkit.startup.recent_crashes", 10);' >> chrome_debugger_profile/prefs.js
3. Open firefox, now pressing the browser toolbox button does nothing

I guess some piece of code is trying to force safe mode, but the toolkit part doesn't know how to handle that? :)

Comment 10

[Jan Honza Odvarko [:Honza] (always need-info? me)]

This is likely fixed by work done in Bug 1120863 - Browser toolbox starts blank and doesn't function with pending updates
Feel free to reopen if you are still experiencing this issue.

Honza