bug#61274: 29.0.60; dabbrev-capf signals errors

[Eli Zaretskii]

> Date: Sat, 4 Feb 2023 17:03:26 +0100
> Cc: 61274@debbugs.gnu.org, monnier@iro.umontreal.ca
> From: Daniel Mendler <mail@daniel-mendler.de>
> 
> On 2/4/23 14:16, Eli Zaretskii wrote:
> > The patch below fixes the error.
> 
> Thanks!

Should I install it?

> > Regarding "No dynamic expansion" error: what did you expect to happen
> > instead and why?  IOW, what is the expected result of having
> > dabbrev-capf alone in completion-at-point-functions, and then typing
> > "x M-TAB"?
> 
> I would expect the completion UI to show a message, instead of an error
> from the Capf. For example if you start emacs -Q, type "nonexistent
> M-TAB" in the scratch buffer to access the normal Elisp completions.
> Then you will see the message "No match" in the minibuffer. If
> `dabbrev-capf' would not throw an error, we would get the same message.

maybe dabbrev-capf is unsuitable to serve as the value of
completion-at-point-functions?

Stefan, any comments?