1607842 - Remote debugging console in about:debugging broken in Firefox 72

Status: RESOLVED WONTFIX

(DevTools :: about:debugging, defect)

Description

[michelesr]

Attachment: Screenshot from 2020-01-08 17-27-49.png

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:72.0) Gecko/20100101 Firefox/72.0

Steps to reproduce:

• connect an android phone running fennec 68.0.3 ESR, with adb and usb debugging enabled

• open firefox 72

• open "about:debugging"

• connect to the android phone

• open the main thread debugging

Actual results:

The whole console is blank, nothing loads

Expected results:

The web console should have initialized properly, like in Firefox 71

Comment 1

[michelesr]

Attachment: browser console

Browser console:

```

Comment 2

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

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 3

[Julian Descottes [:jdescottes]]

Hi michelesr,

For remote debugging, our backward compatibility policy only supports debugging servers at most 2 versions older than the client. This means that ESR68 can be debugged from Firefox 68, 69 or 70. Since the release channel is now 72, you have to use Firefox Desktop ESR68 in order to connect to Fennec (https://www.mozilla.org/en-US/firefox/all/#product-desktop-esr).

We don't actively prevent connections that are outside of the supported range, that's why you were able to use 71 to debug Fennec68ESR. And luckily there were no backward compatibility breaking changes in 71 for your use case. Actively preventing connections is something we might do in the future, it should reduce the friction, see Bug 1492464.

Also, there should be a warning message in about:debugging that mentions the version issue.

Closing as wontfix, but feel free to post here if you have other questions.

Comment 4

[michelesr]

Fair enough, as long as the about:debug remote web console is working properly for supported versions.

Comment 5

[michelesr]

However, I didn't find the usb debugging section in "about:debugging" in Firefox 68.4.1esr. Can you provide advise on how to enable USB debugging on a fresh profile?

I'll attach a screenshot of the about:debugging page.

Comment 6

[michelesr]

Attachment: about:debugging in Firefox 68.4.1esr (GNU/Linux x86_64)

Comment 7

[Julian Descottes [:jdescottes]]

Oh that's very unfortunate, it seems we only enabled the new about:debugging starting with Firefox 69.

You need to go to about:config and set devtools.aboutdebugging.new-enabled to true.
Or you could use WebIDE, which should still be bundled in Firefox 68...

Comment 8

[michelesr]

Thanks Julian, that option did the trick.