Allow `kill-buffer' query to save the buffer first

* lisp/loadup.el ("emacs-lisp/rmc"): Preload.

* lisp/simple.el (kill-buffer--possibly-save): New function to
offer to save the buffer before killing (bug#47075).

* src/buffer.c (Fkill_buffer): Call the new function to query the
user.
(syms_of_buffer): Define symbol.

2 files changed, 20 insertions, 0 deletions

diff --git a/lisp/loadup.el b/lisp/loadup.el
index 1d834da5b28..21a87dbd77b 100644
--- a/lisp/loadup.el
+++ b/lisp/loadup.el
@@ -397,6 +397,9 @@
       (message "Warning: Change in load-path due to site-load will be \
 lost after dumping")))
 
+;; Used by `kill-buffer', for instance.
+(load "emacs-lisp/rmc")
+
 ;; Make sure default-directory is unibyte when dumping.  This is
 ;; because we cannot decode and encode it correctly (since the locale
 ;; environment is not, and should not be, set up).  default-directory
diff --git a/lisp/simple.el b/lisp/simple.el
index f2b3d82a7a5..653cffae62c 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -10560,6 +10560,23 @@ If the buffer doesn't exist, create it first."
   (interactive)
   (pop-to-buffer-same-window (get-scratch-buffer-create)))
 
+(defun kill-buffer--possibly-save (buffer)
+  (let ((response
+         (cadr
+          (read-multiple-choice
+           (format "Buffer %s modified; kill anyway?"
+                   (buffer-name))
+           '((?y "yes" "kill buffer without saving")
+             (?n "no" "exit without doing anything")
+             (?s "save and then kill" "save the buffer and then kill it"))
+           nil nil (not use-short-answers)))))
+    (if (equal response "no")
+        nil
+      (unless (equal response "yes")
+        (with-current-buffer buffer
+          (save-buffer)))
+      t)))
+
 
 
 (provide 'simple)