bug#46374: 28.0.50; Ask me to save buffers only if they are under callers dir

[Juri Linkov <juri@linkov.net>]

> Sorry for the late response: many meetings with investors.
> Then I went on a vacation to my castle in Seychelles.

Oh, I thought you were busy running for President.

>> Why not simply add a new option to the existing variable
>> save-some-buffers-default-predicate?  For example:
>>
>> (defcustom save-some-buffers-default-predicate nil
>>   "Default predicate for `save-some-buffers'."
>>   :group 'auto-save
>>   ;; FIXME nil should not be a valid option, let alone the default,
>>   ;; eg so that add-function can be used.
>>   :type '(choice (const :tag "Default" nil)
>>                  (const :tag "Subdirs of default directory" default-directory)
>>                  (const :tag "Project root" project-root)
>>                  function)
>
> Indeed, this was my initial implemention.
> Then I moved to the one I shared here; I found my second version
> superior for the following reason:
>
> 1. Users can restrict the buffer default directory AND still pass a
>    predicate to filter by any other thing they wish;
>    i.e. you don't need to chose either one of the other.
>
> 2. I find it cleaner having it in a separated option.

I'm not sure if there is a need for adding
another dimension with another option.

But if yes, then still shouldn't a new option
provide a wider choice of restricting predicates
like above?