Re: How to debug "fatal: external diff died, stopping at ..."?

[Jeff Hostetler <git@jeffhostetler.com>]

On 1/9/23 8:35 AM, Sebastian Schuberth wrote:
> Hi,
> 
> similar to this [1] question on StackOverflow, ever since a
> distribution upgrade of my Fedora Linux box (KDE spin, now on release
> 37), my configured diff / merge tool (Beyond Compare 4) crashes with
> "fatal: external diff died, stopping at ..." after displaying the diff
> for the first file, for every operation I've tried so far (including
> resolving merge conflicts). I've also posted to the Beyond Compare
> forums [2], but the people from Scooter Software seem to be clueless
> as well.
> 
> Would anyone have an idea how to debug this?
> 
> PS: I also tried to use an X11 instead of a Wayland session with KDE /
> Plasma, but that did not help.
> 
> [1]: https://askubuntu.com/questions/1437667/git-difftool-with-meld-broken-after-update-to-22-04-fatal-external-diff-died
> [2]: https://forum.scootersoftware.com/forum/beyond-compare-4-discussion/linux-aa/88824-bc4-as-a-git-merge-tool-says-fatal-external-diff-died
> 

You might try turning on Trace2 in Git and see if there is
any extra info there on the child processes.

$ GIT_TRACE2_PERF=1 git difftool ...

or

$ export GIT_TRACE2_PERF=/absolute/path/to/logfile
$ git difftool ...

There you'll be able to see all of the "child_start" and
"child_exit" events for each process that Git starts (at
the "d1" level (and grandchildren at the "d2" level)).

Maybe that'll reveal something.

https://devblogs.microsoft.com/devops/a-deep-dive-into-git-performance-using-trace2/


Hope this helps,
Jeff