emacs-28 f22e9ba9ac: Fix regression in Occur Edit mode

[Eli Zaretskii]

branch: emacs-28
commit f22e9ba9ac64c30d6532a508494b5149c27596e7
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix regression in Occur Edit mode
    
    * lisp/replace.el (occur-after-change-function): Fix the algorithm
    to find the smallest change in some corner cases.  (Bug#53598)
---
 lisp/replace.el | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lisp/replace.el b/lisp/replace.el
index 45bd05d41d..b1cfd7e3f4 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -1413,10 +1413,15 @@ To return to ordinary Occur mode, use 
\\[occur-cease-edit]."
                             (length s1)))))
                      (prefix-len (funcall common-prefix buf-str text))
                      (suffix-len (funcall common-prefix
-                                          (reverse buf-str) (reverse text))))
+                                          (reverse (substring
+                                                    buf-str prefix-len))
+                                          (reverse (substring
+                                                    text prefix-len)))))
                 (setq beg-pos (+ beg-pos prefix-len))
                 (setq end-pos (- end-pos suffix-len))
-                (setq text (substring text prefix-len (- suffix-len)))
+                (setq text (substring text prefix-len
+                                      (and (not (zerop suffix-len))
+                                           (- suffix-len))))
                 (delete-region beg-pos end-pos)
                 (goto-char beg-pos)
                 (insert text)))