Re: master ff3f17ca3cd: choose-completion: Retain the suffix after completion boundary

[Eshel Yaron <me@eshelyaron.com>]

Dmitry Gutov <dmitry@gutov.dev> writes:

> Hi Eshel,
>
> On 17/05/2024 11:56, Eshel Yaron wrote:
[...]
>> I'm afraid there might be another regression, here's what I see:
>
> Thanks for keeping an eye out.
>
>> 1. emacs -Q
>> 2. C-x C-f
>> 3. C-a C-k to clear the minibuffer
>> 4. Insert the path an Emacs checkout, e.g. "~/checkouts/emacs/"
>> 5. Further insert "l/mi"
>> 6. Hit ? to pop the completions list, which includes
>>     "lisp/minibuffer.el" and "leim/MISC-DIC/", among others.
>
> FWIW, I don't see "leim/MISC-DIC" among completions, even if I first
> evaluate (setq completion-ignore-case t).

Weird, perhaps you have read-file-name-completion-ignore-case set to nil
and that takes effect rather than plain completion-ignore-case?

> But the crux of the problem reproduces fine.

Great.

>> 7. Lean on M-<down> to cycle between completion candidates.
>> After the last fix, I see M-<down> accumulate text after point in
>> the
>> minibuffer instead of replacing the part it previously inserted.  Do you
>> see that as well?
>
> Please take the attached patch for a spin.

Nice, this seems to fix the regression at hand, and so far I'm not
seeing any other issues.

> It would be great if someone looked into writing integration tests for
> this somehow. This is brittle stuff, and the variety of scenarios is
> high enough.

I agree.  The default completion UI supports various interactions that
can break in subtle ways, and that's without even configuring stuff.
I'll try to code a couple of test cases when I have the time.


Best,

Eshel