On Fri, Aug 25, 2017 at 9:08 AM Eli Zaretskii <
eliz@gnu.org> wrote:
> From: Kaushal Modi <kaushal.modi@gmail.com>
> Date: Fri, 25 Aug 2017 12:14:23 +0000
>
> I recently discovered an anomaly with my outline mode customization and it boiled down to this unexplained
> behavior.. the outline-minor-mode-hook was getting triggered twice on doing revert-buffer.
Isn't this expected behavior? revert-buffer calls normal-mode, which
first kills all local variables, which involves turning off
outline-minor-mode by calling
(outline-minor-mode -1)
And that calls your hook.
The other time is when normal-mode turns outline-minor-mode ON.
The doc string of outline-minor-mode-hook (and any other hook created
by define-minor-mode) clearly says:
Hook run after entering or leaving ‘outline-minor-mode’.
Hi Eli,
Thanks for reviewing the report. I have now fixed the problem at my end.
Here is an updated MWE to exactly show the problem I was facing:
- I needed to update a local var specific to the major mode.
- The minor mode needed a act a bit differently based on the value of that local variable.
- The problem was that that local variable was getting wiped out after the first call of the minor mode hook and it wasn't getting set correctly by my/text-mode-customization (below example)
=====
(defvar-local my/var 'unknown
"This var is set to the major mode locally.")
(defun modi/debug ()
(message "In outline debug")
(message "buf name: `%S'" (buffer-name))
(message "major-mode: `%S'" major-mode)
(message "my/var: `%S'" my/var))
(add-hook 'outline-minor-mode-hook #'modi/debug)
(add-hook 'text-mode-hook #'outline-minor-mode :append)
(defun my/text-mode-customization ()
(message "In text mode customization")
(setq-local my/var major-mode))
(remove-hook 'text-mode-hook #'my/text-mode-customization)
(add-hook 'text-mode-hook #'my/text-mode-customization :append) ;Culprit!
(global-set-key (kbd "<f5>") (lambda () (interactive) (revert-buffer)))
=====
On doing C-h v text-mode-hook, I saw:
(outline-minor-mode text-mode-hook-identify my/text-mode-customization)
That explained that the outline-minor-mode's hook ran before my/text-mode-customization can set the my/var correctly.
The fix was simply to keep the APPEND arg of add-hook at its default value nil.
The fix was simple but the debug was mind-numbing.. thanks for the help!