Re: Debugging a seldom seen bug (C-g with Ido)

[Stefan Monnier]

> I'm using Ido for all my completion needs, and occasionally when i'm
> trying to abort an active ido-find-file command with C-g, i'm getting
> "[Quit]" appended to the minibuffer, rather than the operation being
> aborted.  As if the keyboard-quit was processed while some buffer other
> than minibuffer was current.
>
> It happens rather rarely and i failed to reliably reproduce it following
> the script from view-lossage.

It's probably timing-dependent.  My guess is that it happens when you it
`C-g` while Emacs is running some ELisp code and it processes the `C-g` as
a (signal 'quit), like what happens when you hit `C-g` to interrupt
execution of ELisp code, rather than by looking it up in the keymaps.

You can try and debug this with (setq debug-on-error t debug-on-quit t)

This setting can be rather annoying, tho (it will bring up a debugger
buffer every time you interrupt ELisp execution with `C-g`), but if you
hit the problem often enough it might be sufficient to catch the bugger
red-handed.

Feel free to send the resulting backtrace here (along with
a description of what you were doing and what you remember seeing on
screen shortly before the problem).


        Stefan