Re: [Emacs-diffs] master 108ce84 2/2: xref--next-error-function: Move xref's window point

[Dmitry Gutov <dgutov@yandex.ru>]

On 3/2/18 3:39 PM, Eli Zaretskii wrote:

>> Try:
>>
>> 1. cd .../emacs/source/dir
>> 2. emacs -Q
>> 3. M-x project-find-regexp RET It is not necessary to RET
>> (The searches for "It is not necessary to", which only occurs in .el files).
>> 4. M-x next-error, do that a few times. Make sure *xref* is still
>> visible (otherwise, you need to tweak the split-threshold variables).
>> 5. Select the window showing the xref buffer, then go back to where you
>> were (by typing 'C-x o' a couple of times).
>> 6. M-x next-error will return to the beginning. Or, if the window point
>> of the xref window is not at the first line, start over from there.
> 
> Is this due to switch-to-buffer-preserve-window-point being t by
> default now?

I want to say yes because that fits my understanding of the problem. But 
(setq switch-to-buffer-preserve-window-point nil) doesn't change neither 
the scenario above, nor its behavior in my work configuration.
>> The reason I figured it's urgent, is step 5 is not necessary with my
>> work configuration (not 'emacs -Q'). It's hard for me to tell now which
>> package/setting/timer has this effect, but it seems reasonable to
>> believe that some other users will see this too. Essentially, the code
>> in emacs-26 currently relies on "undefined behavior", in C terms.
> 
> I'm not sure I see where does "undefined behavior" come from.

"Behavior I don't understand" might be closer to the truth. :-)