bug#40919: 27.0.91; next-error-select-buffer does not always behave as documented

[Dmitry Gutov <dgutov@yandex.ru>]

On 12.06.2020 01:43, Juri Linkov wrote:
>> what kind of functions do they want to put on there?
> 
> Both next-error-buffer-on-selected-frame and next-error-no-navigation-try-current.
> 
>> And/or would they be content to advice-add on
>> next-error-find-buffer-function instead?
> 
> Is it possible to add advice-add by using customization?

No, or at least not yet. But if we know of only one user that wants this 
setup, surely that's not a problem?

By the way, you were going to evaluate the new default. Do you now think 
that it's problematic somehow (and, for instance, the previous was a 
better default), or do you want to change it as a purely personal 
preference?

>>> -(defcustom next-error-find-buffer-function #'ignore
>>> +(defcustom next-error-find-buffer-function '(ignore)
>>
>>                                               ^s, maybe?
> 
> Ok, when using as a hook it could be '-functions', but in case
> of using advice-add it should be still '-function'.

Yup. These are the two options.

>>>       ;; 2. If next-error-last-buffer is an acceptable buffer, use that.
>>>       (if (and next-error-last-buffer
>>>                (next-error-buffer-p next-error-last-buffer avoid-current
>>
>> Should we take the rest of the cases in next-error-find-buffer and move
>> them to the default value of the above hook?
> 
> I don't think so, I don't believe someone might want to customize the
> rest of the cases.

Well, if you're sure about that.

Having them all on the hook seemed logical to me, but indeed I don't 
know how necessary that is.