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

[Dmitry Gutov <dgutov@yandex.ru>]

On 15.06.2020 02:15, Juri Linkov wrote:

>>>> 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?
> 
> It's a general problem that hindered the development of other features
> that might benefit from customizable advice-add (namely set-multi-message).

The Customize UI is definitely not my area, sorry (not as developer, nor 
as a user).

>> 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?
> 
> Only personal preference, it seems the default in master is fine
> for most users.

Very good.

>> Having them all on the hook seemed logical to me, but indeed I don't know
>> how necessary that is.
> 
> The reason why I think no one might want to customize the rest of the cases
> is because I believe that next-error-last-buffer is always non-nil, so
> all other cases (i.e. 3, 4, 5, 6) are useless and never used.  Isn't it so?

change-log-mode doesn't set it (and it shouldn't). Maybe there will be 
other major modes like that. So #3 should be used sometimes.

#4 doesn't seem very intuitive/useful to me, and I don't understand #5 
(when is AVOID-CURRENT non-nil?)