bug#51016: 28.0.50; 'diff-font-lock-prettify' breaks display of outline headers

[Juri Linkov]

> Juri Linkov <juri@linkov.net> writes:
>
>> As noticed in bug#51809, outline-cycle is not bound on hunk headings anymore,
>> only on file headings.  It seems the problem is somewhere here:
>>
>>     (setq diff-outline-regexp
>>           (concat "\\(^diff --git.*\n\\|" diff-hunk-header-re "\\)"))
>>
>> But I don't know why diff-hunk-header-re doesn't match hunk headings
>> in outline-minor-mode.
>
> Hm...  I just tried switching outline-minor-mode on and
> (re-search-forward diff-hunk-header-re), and it seemed to work as
> expected?

Yep, I already tried `(re-search-forward diff-hunk-header-re)' too,
and it works.  But still typing TAB on the hunk heading
with outline-minor-mode-cycle=t does nothing, whereas typing TAB
on the file heading correctly cycles the file diff.