1530861 - Blank Debugger panel when using remote debugging

Status: RESOLVED FIXED

(DevTools :: about:debugging, defect)

Description

[Julian Descottes [:jdescottes]]

This is a backward compatibility issue from Bug 1269919

Prerequisite:

• devtools.toolbox.selectedTool should be set on the client
• client should have Bug 1269919
• server should not have Bug 1269919

STRs:

• open DevTools
• select a Panel
• close DevTools
  (the goal of this step is to set the pref devtools.toolbox.selectedTool, which triggers the bug for some reason)
• open about:debugging-new
• connect to your older server
• inspect any tab
• in about:devtools-toolbox, select the debugger

ER: Debugger UI should display
AR: Debugger UI is blank

The UI crashes because listWorkers doesn't return a workers array:
https://searchfox.org/mozilla-central/rev/dbddac86aadf1d4871fb350bbe66db43728a9f81/devtools/client/debugger/new/src/client/firefox/workers.js#27

Comment 1

[Julian Descottes [:jdescottes]]

Note that simply doing

  let { workers } = await tabTarget.listWorkers();
  workers = workers || [];

at https://searchfox.org/mozilla-central/rev/dbddac86aadf1d4871fb350bbe66db43728a9f81/devtools/client/debugger/new/src/client/firefox/workers.js#27 "fixes" the issue.

Comment 2

[Julian Descottes [:jdescottes]]

Alex, looks like https://hg.mozilla.org/mozilla-central/rev/c018b87959c2 is breaking backwards compatibility, or at least it bricks the debugger UI. Any idea why this would happen? At first glance, I don't understand why this patch would impact a listWorkers() call?

Comment 3

[Alexandre Poirot [:ochameau]]

Thanks for the report, it is a pretty trivial fix.
I never removed an event and it needs special care to not break backward compat.

Comment 4

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1530861 - Acknowledged newSource events sent by remote devices on FF66 and less.

newSource events used to be sent on the target actors on FF66 and before,
this is no longer the case. But we still have to accept them if we connect
to old remotes, otherwise the events are considered as a method reply
and confuses packet ordering.

Comment 5

[Alexandre Poirot [:ochameau]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=74f28b01e5e49fac4322768a94b91dd963dd8fef

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9a25f61c3ca3
Acknowledged newSource events sent by remote devices on FF66 and less. r=jdescottes

Comment 7

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1530861 - Fix typo in deprecated firefox version comment.

Comment 8

[Julian Descottes [:jdescottes]]

thanks for fixing the comment in a followup :)

Comment 9

[Oana Pop-Rus]

https://hg.mozilla.org/mozilla-central/rev/9a25f61c3ca3

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/21e12842278a
Fix typo in deprecated firefox version comment. r=jdescottes

Comment 11

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/21e12842278a