1593569 - ghost breakpoints

Status: RESOLVED WORKSFORME

(DevTools :: Debugger, defect)

Description

[mattias hammar]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:70.0) Gecko/20100101 Firefox/70.0

Steps to reproduce:

I set a breakpoint and changed the source code

Actual results:

if you set a breakpoint and then the source code is changed so that breakpoint falls between two breakpoints enabled lines, that breakpoint becomes a ghost breakpoint. It is not shown, but the debugger still halts on the next line. The real funny part is that you can't remove it. Even with the "remove all breakpoints".
And if you restart the debugger it is still there. Then eventually my code changes again and the breakpoint becomes visible again and I can remove it. Surely annoying that the debugger stops every single time on a line that does not have any code and it is impossible to remove.

Expected results:

well, a ghost breakpoint should either die or be shown on the next ( or previous ) line.

( this bug has been around for a long time now, years... )

Comment 1

[Jason Laster [:jlast]]

Thanks for reporting. We refer to these bugs internally as zombie breakpoints by the way.

• I believe Firefox 71 fixes the issue with "remove all breakpoints" so that all breakpoints are removed.
• I'm surprised zombie bps still exist. Do you think you could make a small example in dbg.glitch.me with a suggestion for a code change that would reproduce this. I usually add a valid breakpoint, then add a line of code and then refresh...

Comment 2

[Jason Laster [:jlast]]

Lastly, thanks for the great bug reports. I'd be happy to chat further on slack as well. I really appreciate that you took the time to report the bugs you're seeing. We were working primarily in github 2-3 years ago and were not always as attentive to bug reports.

We were also working on a re-write, which was very bug prone. So thank you for being patient with us.

https://devtools-html-slack.herokuapp.com/

Comment 3

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

Please see the previous comments.

Thanks!
Honza

Comment 4

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

Since we don't have a test case to see the issue we can't fix it.
Feel free to reopen if you can provide a simple page showing the zombie breakpoint in action.

Honza