Preserve case in query-replace undo

If the user query and replaces 'foo' with 'BAR', then
undo must comeback to 'foo', not to 'FOO' (Bug#31073).
* lisp/replace.el (perform-replace): Bind nocasify to non-nil
value during undo/undo-all actions.
* test/lisp/replace-tests.el (query-replace-undo-bug31073): Add test.

1 files changed, 1 insertions, 0 deletions

diff --git a/lisp/replace.el b/lisp/replace.el
index c28c9b36f05..4916cb138e6 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -2619,6 +2619,7 @@ It must return a string."
                            (let ((stack-idx         0)
                                  (stack-len         (length stack))
                                  (num-replacements  0)
+                                 (nocasify t) ; Undo must preserve case (Bug#31073).
                                  search-string
                                  next-replacement)
                              (while (and (< stack-idx stack-len)