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

[Eli Zaretskii <eliz@gnu.org>]

> Cc: juri@linkov.net, 40919@debbugs.gnu.org, tspiteri@ieee.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Tue, 26 May 2020 02:17:34 +0300
> 
> The attached patch moves case #2 into a new function and makes it the 
> default value of the said defcustom (thus case #2 effectively moves into 
> case #1). As a result, the default behavior doesn't change, but the user 
> will have a much easier time turning off case #2.

Maybe I don't understand something, but it looks to me that this
changes the behavior if next-error-find-buffer-function has a
non-default value: previously what's now
next-error-no-navigation-try-current would be executed after calling
next-error-find-buffer-function, now it isn't.  Is that really
necessary?

> > (Btw, the textual descriptions of the options both in the patch and
> > those already in the code are confusingly obscure, so much so that I
> > don't think I could understand what each one does.)
> 
> Knowing the subject matter somewhat, I think the descriptions are 
> meaningful enough, but to make sense of them one has to understand how 
> the whole feature comes together. E.g. at what times 
> next-error-find-buffer is called.

I think I know something about the subject matter, and still the text
is quite impenetrable for me.

> > All in all, I feel (for quite some time) that this area is
> > over-engineered and keeps bumping into more and more unintended
> > consequences.  Maybe it's time to take a step back and rethink the
> > entire subject?  (But definitely not on the release branch.)
> 
> That's what we're doing here.

Sigh.