Re: Undo defalias

[Óscar Fuentes]

Stefan Monnier via Users list for the GNU Emacs text editor
<help-gnu-emacs@gnu.org> writes:

>> The problem was caused by aggressive-indent-mode.el. It uses
>>
>> (cl-letf (((symbol-function 'message) #'ignore))
>>  ...
>
> So either:
> - you're still within the `cl-letf`.  In that case
>   `abort-recursive-edit` or some such should fix the problem.

I don't have the problematic session around anymore, but I recall seeing
a *Backtrace* buffer among the list of existing buffers. However, IIRC
Emacs says that a recursive edit is active and that indication was not
there.

> - you're not within the `cl-letf` any more, in which case the question
>   becomes: how come `cl-letf` didn't restore the previous value?
>   `cl-letf` uses `unwind-protect` so it should restore the previous
>   binding reliably even in case of errors.
>
> [ There's admittedly the possibility/risk that you hit `C-g` (or some
>   similar error occurred) right at the specific moment when `cl-letf`
>   was executing the second part of the `unwind-protect` (i.e. the one
>   that reset `message` to its previous definition).
>   That's a known hole in our system.  ]

That's also quite plausible, indeed. I tend to use C-g quite frequently.