Add a new command `revert-buffer-quick'

* doc/emacs/files.texi (Reverting): Document it.
* lisp/bindings.el (ctl-x-x-map): Bind `C-x x g' to
`revert-buffer-quick' instead.

* lisp/files.el (revert-buffer-quick-short-answers): New user option.
(revert-buffer-quick): New command (bug#49869).

doc/emacs/files.texi

@@ -948,7 +948,7 @@ Manual}).  For customizations, see the Custom group @code{time-stamp}.
 then change your mind, you can @dfn{revert} the changes and go back to
 the saved version of the file.  To do this, type @kbd{C-x x g}.  Since
 reverting unintentionally could lose a lot of work, Emacs asks for
-confirmation first.
+confirmation first if the buffer is modified.
 
   The @code{revert-buffer} command tries to position point in such a
 way that, if the file was edited only slightly, you will be at
@@ -991,6 +991,17 @@ revert it automatically if it has changed---provided the buffer itself
 is not modified.  (If you have edited the text, it would be wrong to
 discard your changes.)
 
+@vindex revert-buffer-quick-short-answers
+@findex revert-buffer-quick
+  The @kbd{C-x x g} keystroke is bound to the
+@code{revert-buffer-quick} command.  This is like the
+@code{revert-buffer} command, but prompts less.  Unlike
+@code{revert-buffer}, it will not prompt if the current buffer visits
+a file, and the buffer is not modified.  It also respects the
+@code{revert-buffer-quick-short-answers} user option.  If this option
+is non-@code{nil}, use a shorter @kbd{y/n} query instead of a longer
+@kbd{yes/no} query.
+
   You can also tell Emacs to revert buffers automatically when their
 visited files change on disk; @pxref{Auto Revert}.
 

etc/NEWS

@@ -310,7 +310,7 @@ search buffer due to too many matches being highlighted.
 +++
 ** A new keymap for buffer actions has been added.
 The 'C-x x' keymap now holds keystrokes for various buffer-oriented
-commands.  The new keystrokes are 'C-x x g' ('revert-buffer'),
+commands.  The new keystrokes are 'C-x x g' ('revert-buffer-quick'),
 'C-x x r' ('rename-buffer'), 'C-x x u' ('rename-uniquely'), 'C-x x n'
 ('clone-buffer'), 'C-x x i' ('insert-buffer'), 'C-x x t'
 ('toggle-truncate-lines') and 'C-x x f' ('font-lock-update').
@@ -2394,6 +2394,16 @@ This command, called interactively, toggles the local value of
 
 ** Miscellaneous
 
++++
+*** New command 'revert-buffer-quick'.
+This is bound to 'C-x x g' and is like `revert-buffer', but prompts
+less.
+
++++
+*** New user option 'revert-buffer-quick-short-answers'.  This
+controls how the new 'revert-buffer-quick' (`C-x x g') command
+prompts.
+
 ---
 *** fileloop will now skip missing files instead of signalling an error.
 

lisp/bindings.el

@@ -1469,7 +1469,7 @@ if `inhibit-field-text-motion' is non-nil."
 (defvar ctl-x-x-map
   (let ((map (make-sparse-keymap)))
     (define-key map "f" #'font-lock-update)
-    (define-key map "g" #'revert-buffer)
+    (define-key map "g" #'revert-buffer-quick)
     (define-key map "r" #'rename-buffer)
     (define-key map "u" #'rename-uniquely)
     (define-key map "n" #'clone-buffer)

lisp/files.el

@@ -6561,6 +6561,37 @@ details on the arguments, see `revert-buffer'."
           (revert-buffer-with-fine-grain-success-p)
         (fmakunbound 'revert-buffer-with-fine-grain-success-p)))))
 
+(defcustom revert-buffer-quick-short-answers nil
+  "How much confirmation to be done by the `revert-buffer-quit' command.
+If non-nil, use `y-or-n-p' instead of `yes-or-no-p'."
+  :version "28.1"
+  :type 'boolean)
+
+(defun revert-buffer-quick (&optional auto-save)
+  "Like `revert-buffer', but asks for less confirmation.
+If the current buffer is visiting a file, and the buffer is not
+modified, no confirmation is required.
+
+This command heeds the `revert-buffer-quick-short-answers' user option.
+
+If AUTO-SAVE (the prefix argument), offer to revert from latest
+auto-save file, if that is more recent than the visited file."
+  (interactive "P")
+  (cond
+   ;; If we've visiting a file, and we have no changes, don't ask for
+   ;; confirmation.
+   ((and buffer-file-name
+         (not (buffer-modified-p)))
+    (revert-buffer (not auto-save) t)
+    (message "Reverted buffer"))
+   ;; Heed `revert-buffer-quick-short-answers'.
+   (revert-buffer-quick-short-answers
+    (let ((use-short-answers t))
+      (revert-buffer (not auto-save))))
+   ;; Call `revert-buffer' normally.
+   (t
+    (revert-buffer (not auto-save)))))
+
 (defun recover-this-file ()
   "Recover the visited file--get contents from its last auto-save file."
   (interactive)