Re: master 9904376c797: Support calling 'project-current' with custom prompt

[Dmitry Gutov]

Hi Eshel,

On 23/10/2024 09:54, Eshel Yaron wrote:
> Hi Dmitry,
>
> Dmitry Gutov <dgutov@yandex.ru> writes:
>
> > branch: master
> > commit 9904376c797665de47ff760bcf8c2fe33d7ae625
> > Author: Dmitry Gutov <dmitry@gutov.dev>
> > Commit: Dmitry Gutov <dmitry@gutov.dev>
> >
> >      Support calling 'project-current' with custom prompt
> >      
>
> [...]
>
> > -      (setq directory (funcall project-prompter)
> > +      (setq directory (if (stringp maybe-prompt)
> > +                          (funcall project-prompter maybe-prompt)
> > +                        (funcall project-prompter))
>
> JFYI, I'm using a custom project-prompter, which was not prepared to be
> called with an argument, so I got some unexpected errors until I
> realized what changed.  A quick lookup online shows that although this
> option is quite new, a few others already set it to a custom function,
> so it might be worth catching the "Wrong number of arguments" error.

It's good of you to bring this up, but under what conditions do you 
encounter the breakage? Are there 3rd-party callers of 'project-current' 
already as well, that pass a string as MAYBE-PROMPT? If so, that's a 
little quicker than I expected. :)

Catching an error might be a fine approach, but then a lot of people 
would miss out on the reason why the provided prompt is not used.

> Also, I'd like to update the docstring of project-prompter along the
> following lines, if it looks right to you:
>
> diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
> index 3cdaa7c2a76..6383bdc95d2 100644
> --- a/lisp/progmodes/project.el
> +++ b/lisp/progmodes/project.el
> @@ -199,7 +199,9 @@ project-current-directory-override
>   
>   (defcustom project-prompter #'project-prompt-project-dir
>     "Function to call to prompt for a project.
> -Called with no arguments and should return a project root dir."
> +The function is either called with no arguments or with one argument,
> +which is the prompt string to use when prompting.  It should return a
> +project root directory."
>     :type '(choice (const :tag "Prompt for a project directory"
>                           project-prompt-project-dir)
>                    (const :tag "Prompt for a project name"

Thanks, I've pushed a slight edit of that (sorry it went out without 
attribution). Also updated the corresponding NEWS entry.