1752546 - about:debugging doesn't update servers tab's URL for first navigation (away from about:newtab)

Status: RESOLVED FIXED

(DevTools :: about:debugging, defect)

Description

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:98.0) Gecko/20100101 Firefox/98.0 ID:20220123214850

Having the client connected via about:debugging to the server (like Firefox DevEdition) the first navigation within the first tab that shows about:newtab on the server side is not reflected under tabs for the client. When navigating the client still sees about:newtab and clicking that tab will fail because the underlying windowGlobal does no longer exist.

Julian mentioned that this is an old bug but I haven't found an existing bug so just filing it.

Comment 1

[Julian Descottes [:jdescottes]]

Thanks for filing!

The root cause of the issue is that we only refresh our tabs when we receive a "tabListChanged", coming from the root actor: https://searchfox.org/mozilla-central/rev/7056a708787621758bef9793a93aa7ca8375eeef/devtools/server/actors/root.js#311 . This event is a bit hard to track, but it should be driven from BrowserTabList and emitted after the following platform events:

• "TabOpen"
• "TabSelect"
• "TabAttrModified"
• "TabClose"
• "pagetitlechanged"

I assume "pagetitlechanged" should react to navigations and page loads (even if it's a very unexpected way to monitor this)? At least it was probably the intent.

Note that we actually also have this issue with local tab debugging. But we usually don't see it because when we do local tab debugging, we select tabs back and forth to switch between the about:debugging tab and the target tab. And the tab selection will trigger a tabListChanged which will refresh the list.

Will try to see why "pagetitlechanged" doesn't behave as expected.

Comment 2

[Julian Descottes [:jdescottes]]

Attachment: Bug 1752546 - [devtools] Update about:debugging tab list when a page navigates in the connected runtime

About:debugging seems to be the only consumer of the tabListChanged event at this point.
One of the internal events used by about:debugging was not properly handled. Added a minor fix to change that and added a new mochitest for about:debugging.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d026ced90bda
[devtools] Update about:debugging tab list when a page navigates in the connected runtime r=bomsy

Comment 4

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/d026ced90bda