Hi Juri,

Juri Linkov <juri@linkov.net> writes:

>>> (...)  Also xref works nicely, although I don't know why it requires
>>> `outline-apply-default-state' after enabling `outline-minor-mode':
>>
>> It's a mistake to rely on `hack-local-variables-hook' to call
>> `outline-apply-default-state' when Outline minor mode is enabled since
>> `hack-local-variables-hook' is run after processing a file's local
>> variable specs.
>
> There is also such a case possible where the file begins with a prop-line:
>
>   # -*- mode: outline-minor; -*-
>
> and ends with the Local Variables section, e.g.:
>
>   # outline-default-state: 2
>
> `hack-local-variables-hook' can handle such case in `outline-minor-mode'.
>

This usage of "mode:" looks quite exotic to me. Isn't outine-minor a
minor mode? According to the documentation:

   The special variable/value pair ‘mode: MODENAME;’, if present,
   specifies a major mode (without the “-mode” suffix).

I prefer not support this if possible.

>> I'll send an updated patch after some time using this.
>
> Now you can take in use a new hook added in bug#52855 that allows
> applying the default state after vc-diff finishes:
>
>   (add-hook 'vc-diff-finish-functions 'outline-apply-default-state)

Thanks, I updated my configuration to the following:

(add-hook 'diff-mode-hook #'(lambda ()
			      (setq outline-default-state 1
				    outline-default-rules
				    '(subtree-is-long
				      subtree-has-long-lines
				      (match-regexp . "NEWS\\|test\\|package-lock\\.json\\|poetry\\.lock")))))

(add-hook 'vc-diff-finish-functions
	  #'(lambda ()
	      (when outline-minor-mode
		(outline-apply-default-state))))

(add-hook 'xref-after-update-hook
          #'(lambda ()
              (setq outline-regexp (if (eq xref-file-name-display 'abs)
                                       "/" "[^ 0-9]")
                    outline-default-state 1
                    outline-default-rules '((match-regexp . "ChangeLog\\|test/manual/etags")))
              (outline-minor-mode)))

Here is an updated patch (just rebased my local branch, some minor
conflicts appeared in outline.el):