Re: `org-fill-paragraph' (`M-q') in Org Mode source blocks

[Ihor Radchenko]

Sébastien Miquel <sebastien.miquel@posteo.eu> writes:

>> Try
>> 1. emacs -Q
>> 2. insert
>> ;; A comment
>> (+ 2 2)
>> 3. M-h M-q
>> 
>> Is it emacs-lisp-mode bug? Or is it illegal to fill-region in source
>> code buffers?
>
> I think the original report is about M-q, not M-h M-q. M-q behaves as 
> expected in emacs-lisp-mode.
>
> Currently, org-fill-paragraph will not work properly when called inside 
> src blocks. This can be easily fixed, but probably requires yet another 
> org-fill-paragraph-act-natively variable.

See the attached.
I am not sure if we really need the variable.
AFAIU, acting natively was the default in the past for M-q with no
region selection. Then, I "fixed" some bug report in 05ee1e6ee06db and
introduced the bug herein.

>From 8777839a4fe5da6c9a780eac946e1a8a892d4f22 Mon Sep 17 00:00:00 2001
Message-Id: 
<8777839a4fe5da6c9a780eac946e1a8a892d4f22.1664788728.git.yantar92@gmail.com>
From: Ihor Radchenko <yantar92@gmail.com>
Date: Mon, 3 Oct 2022 17:03:15 +0800
Subject: [PATCH] org-fill-element: Respect region selection when filling
 src-block

* lisp/org.el (org-fill-element): When region is not active, run
`fill-paragraph' at point inside src block.  When region is active and
within src block boundaries, run `fill-paragraph' preserving the
region.  When region is active and crosses src block boundaries, fill
the whole src block.

Reported-by: Fabio Natali <me@fabionatali.com>
Fixes: 201b44de-1f97-1b23-1767-970ee00f259c@posteo.eu">https://orgmode.org/list/201b44de-1f97-1b23-1767-970ee00f259c@posteo.eu
---
 lisp/org.el | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/lisp/org.el b/lisp/org.el
index 036384a04..23cf4198e 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -19135,11 +19135,18 @@ (defun org-fill-element (&optional justify)
       ;; the buffer.  In that case, ignore filling.
       (cl-case (org-element-type element)
        ;; Use major mode filling function is source blocks.
-       (src-block (org-babel-do-in-edit-buffer
-                    (push-mark (point-min))
-                    (goto-char (point-max))
-                    (setq mark-active t)
-                    (funcall-interactively #'fill-paragraph justify 'region)))
+        (src-block
+         (let ((regionp (region-active-p)))
+           (org-babel-do-in-edit-buffer
+            ;; `org-babel-do-in-edit-buffer' will preserve region if it
+            ;; is within src block contents.  Otherwise, the region
+            ;; crosses src block boundaries.  We re-fill the whole src
+            ;; block in such scenario.
+            (when (and regionp (not (region-active-p)))
+              (push-mark (point-min))
+              (goto-char (point-max))
+              (setq mark-active t))
+            (funcall-interactively #'fill-paragraph justify 'region))))
        ;; Align Org tables, leave table.el tables as-is.
        (table-row (org-table-align) t)
        (table
-- 
2.35.1

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
Support Org development at <https://liberapay.com/org-mode>,
or support my work at <https://liberapay.com/yantar92>