Fix corner case in query-replace-regexp undo

This commit fixes Bug#31492.
* lisp/replace.el (replace-match-maybe-edit): Preserve match data.

* test/lisp/replace-tests.el (query-replace-undo-bug31492): Add test.

1 files changed, 4 insertions, 0 deletions

diff --git a/lisp/replace.el b/lisp/replace.el
index 3503b656d9c..a17dd19b0d3 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -2214,6 +2214,10 @@ passed in.  If LITERAL is set, no checking is done, anyway."
             noedit nil)))
   (set-match-data match-data)
   (replace-match newtext fixedcase literal)
+  ;; `query-replace' undo feature needs the beginning of the match position,
+  ;; but `replace-match' may change it, for instance, with a regexp like "^".
+  ;; Ensure that this function preserves the match data (Bug#31492).
+  (set-match-data match-data)
   ;; `replace-match' leaves point at the end of the replacement text,
   ;; so move point to the beginning when replacing backward.
   (when backward (goto-char (nth 0 match-data)))