Re: [BUG] org-delete-indentation on region doesn't work when END is before BEGIN [9.6.1 (release_9.6.1-40-g3d817c @ /home/sbaugh/.local/src/emacs29/lisp/org/)]

[Ihor Radchenko]

Spencer Baugh <sbaugh@janestreet.com> writes:

> 1. emacs -Q
> 2. Insert the following in an org-mode buffer
> * head
> a
> b
> 3. C-x h M-^ and note that it's now formatted as:
> a
> b
>  * head

`org-delete-indentation' did not support regions properly.
I tried to make things more consistent with `delete-indentation in the
attached patch.

May you please test the patch and let me know if there are any other
inconsistencies you observe?

>From 6e9a09dd74e0fcb38563b1042163e95e3e43c4da Mon Sep 17 00:00:00 2001
Message-Id: 
<6e9a09dd74e0fcb38563b1042163e95e3e43c4da.1681642978.git.yantar92@posteo.net>
From: Ihor Radchenko <yantar92@posteo.net>
Date: Sun, 16 Apr 2023 13:00:40 +0200
Subject: [PATCH] org-delete-indentation: Support region selection

* lisp/org.el (org-delete-indentation): Support active region when the
first line in region is a heading.  Clarify in the docstring that
region is ignored with prefix argument.

Reported-by: Spencer Baugh <sbaugh@janestreet.com>
Link: ier3552edfr.fsf@janestreet.com">https://orgmode.org/list/ier3552edfr.fsf@janestreet.com
---
 lisp/org.el | 41 +++++++++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/lisp/org.el b/lisp/org.el
index 26d2a8610..9422fd587 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -17675,41 +17675,50 @@ (defun org-kill-note-or-show-branches ()
           (org-fold-show-branches)
           (org-fold-hide-archived-subtrees beg end)))))
 
-(defun org-delete-indentation (&optional arg)
+(defun org-delete-indentation (&optional arg beg end)
   "Join current line to previous and fix whitespace at join.
 
 If previous line is a headline add to headline title.  Otherwise
 the function calls `delete-indentation'.
 
-I.e. with a non-nil optional argument, join the line with the
-following one.  If there is a region then join the lines in that
-region."
-  (interactive "*P")
+If there is a region (BEG END), then join the lines in that region.
+
+With a non-nil prefix ARG, join the line with the following one,
+ignoring region."
+  (interactive
+   (cons current-prefix-arg
+         (when (and (not current-prefix-arg) (use-region-p))
+           (list (region-beginning) (region-end)))))
+  (unless (and beg end)
+    ;; No region selected or BEG/END arguments not passed.
+    (setq beg (line-beginning-position (if arg 1 0))
+          end (line-end-position (if arg 2 1))))
   (if (save-excursion
-       (beginning-of-line (if arg 1 0))
-       (let ((case-fold-search nil))
-         (looking-at org-complex-heading-regexp)))
+        (goto-char beg)
+        (beginning-of-line)
+        (and (< (line-end-position) end)
+             (let ((case-fold-search nil))
+              (looking-at org-complex-heading-regexp))))
       ;; At headline.
       (let ((tags-column (when (match-beginning 5)
                           (save-excursion (goto-char (match-beginning 5))
                                           (current-column))))
-           (string (concat " " (progn (when arg (forward-line 1))
-                                      (org-trim (delete-and-extract-region
-                                                 (line-beginning-position)
-                                                 (line-end-position)))))))
-       (unless (bobp) (delete-region (point) (1- (point))))
+           string)
+        (goto-char beg)
+        ;; Join all but headline.
+        (save-excursion (save-match-data (delete-indentation nil 
(line-beginning-position 2) end)))
+        (setq string (org-trim (delete-and-extract-region (line-end-position) 
(line-end-position 2))))
        (goto-char (or (match-end 4)
                       (match-beginning 5)
                       (match-end 0)))
        (skip-chars-backward " \t")
-       (save-excursion (insert string))
+       (save-excursion (insert " " string))
        ;; Adjust alignment of tags.
        (cond
         ((not tags-column))            ;no tags
         (org-auto-align-tags (org-align-tags))
         (t (org--align-tags-here tags-column)))) ;preserve tags column
-    (let ((current-prefix-arg arg))
-      (call-interactively #'delete-indentation))))
+    (funcall-interactively #'delete-indentation arg beg end)))
 
 (defun org-open-line (n)
   "Insert a new row in tables, call `open-line' elsewhere.
-- 
2.40.0

-- 
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>