Subject: 30.0.50; [PATCH] c-ts-common-comment-indent-new-line does nothing when the comment line in a block starts with whitespace.

From: Vincenzo Pupillo <[email-masked]>
Date: Mon, 22 Apr 2024 22:16:07 +0200

Hello, 
the new function c-ts-common-comment-indent-new-line has a different behavior 
from comment-indent-new-line in c-mode.
In a comment block like this:
/*
   Lorem ipsum dolor sit amet, consectetur adipiscing elit, 
   sed do eiusmod tempor incididunt ut labore et dolore magna aliqua
*/
M-j does not break the line or indent. The cursor simply stands still.
The attached patch handles this case.

Thank you.
V.
>From aa0b1f1d25a068b0386eeb81bab564465b31399e Mon Sep 17 00:00:00 2001
From: Vincenzo Pupillo <[email-masked]>
Date: Mon, 22 Apr 2024 21:05:49 +0200
Subject: [PATCH] Cover more c-ts-common-comment-indent-new-line.

* lisp/progmodes/c-ts-common.el:
(c-ts-common-comment-indent-new-line): Handles the case of comments in a
comment block that begin with whitespaces.
---
 lisp/progmodes/c-ts-common.el | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/lisp/progmodes/c-ts-common.el b/lisp/progmodes/c-ts-common.el
index 735126e1eac..025703d7fce 100644
--- a/lisp/progmodes/c-ts-common.el
+++ b/lisp/progmodes/c-ts-common.el
@@ -317,7 +317,16 @@ c-ts-common-comment-indent-new-line
     (let ((prefix (match-string 1)))
       (if soft (insert-and-inherit ?\n) (newline 1))
       (delete-region (line-beginning-position) (point))
-      (insert prefix)))))
+      (insert prefix)))
+
+   ;; Line starts with whitespaces
+   ((save-excursion
+      (beginning-of-line)
+      (looking-at (rx (* " "))))
+    (let ((whitespaces (match-string 0)))
+      (if soft (insert-and-inherit ?\n) (newline 1))
+      (delete-region (line-beginning-position) (point))
+      (insert whitespaces)))))
 
 ;;; Statement indent
 
-- 
2.44.0