From 89f0853f1e902778076ae63d0cb21f99d824cbac Mon Sep 17 00:00:00 2001
From: Juri Linkov <juri@linkov.net>
Date: Tue, 4 Nov 2025 20:02:28 +0200
Subject: [PATCH] Use 'read-char-choice' in 'ask-user-about-lock' (bug#79664)

* lisp/userlock.el (ask-user-about-lock): Use 'read-char-choice'
instead of 'read-char'.

* lisp/subr.el (read-char-choice-with-read-key): Add fallback
cond-branch to show a message with required keys.
---
 lisp/subr.el     | 11 ++++++++++-
 lisp/userlock.el | 16 ++++++++--------
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/lisp/subr.el b/lisp/subr.el
index ef08618f467..a5f8ead0a1b 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -3745,7 +3745,16 @@ causes it to evaluate `help-form' and display the result."
 	     ((and (null esc-flag) (eq char ?\e))
 	      (setq esc-flag t))
 	     ((memq char '(?\C-g ?\e))
-	      (keyboard-quit))))))))
+	      (keyboard-quit))))
+	   (t
+	    (beep)
+	    (message "Please type %s"
+		     (substitute-command-keys
+		      (mapconcat (lambda (c)
+				   (format "\\`%s'"
+					   (single-key-description c)))
+				 chars ", ")))
+	    (sit-for 3))))))
     ;; Display the question with the answer.  But without cursor-in-echo-area.
     (message "%s%s" prompt (char-to-string char))
     char))
diff --git a/lisp/userlock.el b/lisp/userlock.el
index 583e13e8b2f..9c1c73cbc8c 100644
--- a/lisp/userlock.el
+++ b/lisp/userlock.el
@@ -51,7 +51,8 @@ You can redefine this function to choose among those three alternatives
 in any way you like."
   (discard-input)
   (save-window-excursion
-    (let (answer short-opponent short-file)
+    (let ((choices `(?s ?q ?p ?S ?Q ?P ?\C-g ?? ,help-char))
+          prompt short-opponent short-file answer)
       (setq short-file
 	    (if (> (length file) 22)
 		(concat "..." (substring file (- (length file) 22)))
@@ -63,16 +64,15 @@ in any way you like."
 		  (concat (substring opponent 0 13) "..."
 			  (match-string 0 opponent)))
 	      opponent))
+      (setq prompt (format-message
+                    (substitute-command-keys
+                     "%s locked by %s: (\\`s', \\`q', \\`p', \\`?')? ")
+                    short-file short-opponent))
       (while (null answer)
 	(when noninteractive
           (signal 'file-locked (list file opponent "Cannot resolve lock conflict in batch mode")))
-        (message (substitute-command-keys
-                  "%s locked by %s: (\\`s', \\`q', \\`p', \\`?')? ")
-                 short-file short-opponent)
-	(let ((tem (let ((inhibit-quit t)
-			 (cursor-in-echo-area t))
-		     (prog1 (downcase (read-char))
-		            (setq quit-flag nil)))))
+        (let ((tem (prog1 (downcase (read-char-choice prompt choices t))
+		     (setq quit-flag nil))))
 	  (if (= tem help-char)
 	      (ask-user-about-lock-help)
 	    (setq answer (assoc tem '((?s . t)