bug#74361: [PATCH] New option xref-navigation-display-window-action

[Juri Linkov <juri@linkov.net>]

>> >   (make-obsolete-variable
>> >    'display-comint-buffer-action
>> >    "use a `(category . comint)' condition in `display-buffer-alist'."
>> >    "30.1")
>> 
>> The categories are a replacement only for customization.
>> But all display-buffer calls should still contain
>> `(category . comint)' that currently presented
>> in these variables.  IOW, the variables currently
>> are used in two ways:
>> 1. as the default values for display-buffer calls
>> 2. as user options
>> 
>> But now customization is supposed to be only with
>> the help of `(category . comint)' in `display-buffer-alist'.
>> So these variable will be used only in display-buffer calls.
>> 
>> > So if some user wants to take our advice and modernize his/her
>> > customizations to use '(category . comint)' instead of
>> > display-comint-buffer-action, the customization will stop working for
>> > him/her when we remove those obsolete options in some future Emacs
>> > version.  Right?  Or what am I missing?
>> 
>> These are two possible solutions:
>> 1. Demote these options to variables not intended for customization.
>> 2. Move their current default values to display-buffer calls.
>
> I expected to see us do #2 at the same time we deprecated the user
> options.  I don't understand why we didn't do that.  The deprecation
> message clearly tells users not to use these variables, so it's
> reasonable to expect them to be deleted.  Moreover, their presence in
> our sources is a potential cause for byte-compilation warnings.

Immediate #2 will break customization for many users.
We have to give enough time between two releases
to allow the users to see a warning and adapt their
config files to upcoming deletion of these options.