spacemacs-defaults: Prompt to save a buffer for certain operations (#15331)

layers/+spacemacs/spacemacs-defaults/funcs.el

@@ -285,7 +285,6 @@ Dedicated (locked) windows are left untouched."
   (interactive "p")
   (spacemacs/rotate-windows-forward (* -1 count)))
 
-
 (if (configuration-layer/package-used-p 'winum)
     (progn
       (defun spacemacs/move-buffer-to-window (windownum follow-focus-p)
@@ -668,6 +667,19 @@ If the universal prefix argument is used then kill the windows too."
     (when (equal '(4) arg) (delete-other-windows))
     (message "Buffers deleted!")))
 
+(defun spacemacs//confirm-kill-buffer ()
+  "Prompt the user to save a buffer to a file before killing it.
+This skips the following buffers:
+- A buffer with non-nil value of variable `buffer-file-name'.
+  Or in other words, a buffer who has a file associated with.
+  Emacs by default prompts the user to save it if it's modified.
+- A buffer derived from `special-mode'."
+  (when (and (not buffer-file-name)
+             (buffer-modified-p)
+             (not (derived-mode-p 'special-mode))
+             (not (yes-or-no-p (format "Buffer %S modified; kill anyway? " (buffer-name)))))
+    (save-buffer)))
+
 ;; from http://dfan.org/blog/2009/02/19/emacs-dedicated-windows/
 (defun spacemacs/toggle-current-window-dedication ()
   "Toggle dedication state of a window. Commands that change the buffer that a
@@ -837,13 +849,12 @@ variable."
                (concat dotspacemacs-template-directory ".spacemacs.template")))
 
 (defun spacemacs/new-empty-buffer (&optional split)
-  "Create a new buffer called: untitled<n>
+  "Create a new buffer called: \"untitled\".
 
-The SPLIT argument decides where the buffer opens:
-Value                                Buffer
-`nil'                                current window
-`left', `below', `above' or `right'  split window
-`frame'                              new frame
+SPLIT decides where the buffer opens:
+- nil, open in current window.
+- `left', `below', `above' or `right', split the window in the given direction.
+- `frame', open in new frame.
 
 If the variable `dotspacemacs-new-empty-buffer-major-mode' has been set,
 then apply that major mode to the new buffer."
@@ -858,6 +869,9 @@ then apply that major mode to the new buffer."
     ;; Prompt to save on `save-some-buffers' with positive PRED
     (with-current-buffer newbuf
       (setq-local buffer-offer-save t)
+      (add-hook 'kill-buffer-hook
+                #'spacemacs//confirm-kill-buffer
+                nil t)
       (when dotspacemacs-new-empty-buffer-major-mode
         (funcall dotspacemacs-new-empty-buffer-major-mode)))
     ;; pass non-nil force-same-window to prevent `switch-to-buffer' from
@@ -1659,11 +1673,14 @@ if prefix argument ARG is given, switch to it in an other, possibly new window."
     (if arg
         (switch-to-buffer-other-window (get-buffer-create "*scratch*"))
       (switch-to-buffer (get-buffer-create "*scratch*")))
-    (when (and (not exists)
-               (not (eq major-mode dotspacemacs-scratch-mode))
-               (fboundp dotspacemacs-scratch-mode))
-      (funcall dotspacemacs-scratch-mode)
-      (run-hooks 'spacemacs-scratch-mode-hook))))
+    (when (not exists)
+      (add-hook 'kill-buffer-hook
+                #'spacemacs//confirm-kill-buffer
+                nil t)
+      (when (and (not (eq major-mode dotspacemacs-scratch-mode))
+                 (fboundp dotspacemacs-scratch-mode))
+        (funcall dotspacemacs-scratch-mode)
+        (run-hooks 'spacemacs-scratch-mode-hook)))))
 
 (defvar spacemacs--killed-buffer-list nil
   "List of recently killed buffers.")