From 0065621d0d36112922792d7c46085230e999cba3 Mon Sep 17 00:00:00 2001
From: Stefan Monnier
Date: Wed, 13 Sep 2023 18:49:55 -0400
Subject: (report_overlay_modification): Fix bug#65929

Somehow the new overlay code in Emacs-29 changed slightly
the test to decide when to run the `modification-hooks` of overlays,
with the consequence that these hook functions end up being executed
also when text is deleted right after an empty overlay, which is
contrary to Emacs-28 behavior as well as contrary to the Texinfo doc.

* src/buffer.c (report_overlay_modification): Better reproduce the
Emacs-28 code.

* test/src/buffer-tests.el (overlay-modification-hooks):
Add corresponding test.
---
 src/buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'src/buffer.c')

diff --git a/src/buffer.c b/src/buffer.c
index 252231357bc..db362ffe7b0 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -4091,7 +4091,7 @@ report_overlay_modification (Lisp_Object start, Lisp_Object end, bool after,
 	    }
 	  /* Test for intersecting intervals.  This does the right thing
 	     for both insertion and deletion.  */
-	  if (! insertion || (end_arg > obegin && begin_arg < oend))
+	  if (end_arg > obegin && begin_arg < oend)
 	    {
 	      Lisp_Object prop = Foverlay_get (overlay, Qmodification_hooks);
 	      if (!NILP (prop))
-- 
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