magit-slow-confirm: new option

Re #2752.

lisp/git-rebase.el

@@ -419,7 +419,7 @@ running 'man git-rebase' at the command line) for details."
     (setq save-place nil)))
 
 (defun git-rebase-cancel-confirm (force)
-  (or (not (buffer-modified-p)) force (y-or-n-p "Abort this rebase? ")))
+  (or (not (buffer-modified-p)) force (magit-y-or-n-p "Abort this rebase? ")))
 
 (defun git-rebase-autostash-save ()
   (--when-let (magit-file-line (magit-git-dir "rebase-merge/autostash"))

lisp/magit-utils.el

@@ -192,6 +192,15 @@ Global settings:
                       (const stage-all-changes) (const unstage-all-changes)
                       (const safe-with-wip))))
 
+(defcustom magit-slow-confirm nil
+  "Whether to ask user \"y or n\" or \"yes or no\" questions.
+When this is nil (the default), then `y-or-n-p' is used when the
+user has to confirm a potentially destructive action.  When this
+is non-nil, then `yes-or-no-p' is used instead."
+  :package-version '(magit . "2.9.0")
+  :group 'magit-commands
+  :type 'boolean)
+
 (defcustom magit-no-message nil
   "A list of messages Magit should not display.
 
@@ -367,6 +376,13 @@ This is similar to `read-string', but
            ',(mapcar 'car clauses))
      ,@(--map `(,(car it) ,@(cddr it)) clauses)))
 
+(defun magit-y-or-n-p (prompt)
+  "Ask user a \"y or n\" or a \"yes or no\" question.
+Also see option `magit-slow-confirm'."
+  (if magit-slow-confirm
+      (yes-or-no-p prompt)
+    (y-or-n-p prompt)))
+
 (cl-defun magit-confirm (action &optional prompt prompt-n (items nil sitems))
   (declare (indent defun))
   (setq prompt-n (format (concat (or prompt-n prompt) "? ") (length items))
@@ -384,9 +400,9 @@ This is similar to `read-string', but
                                    unstage-all-changes))))))
          (or (not sitems) items))
         ((not sitems)
-         (y-or-n-p prompt))
+         (magit-y-or-n-p prompt))
         ((= (length items) 1)
-         (and (y-or-n-p prompt) items))
+         (and (magit-y-or-n-p prompt) items))
         ((> (length items) 1)
          (let ((buffer (get-buffer-create " *Magit Confirm*")))
            (with-current-buffer buffer
@@ -395,7 +411,7 @@ This is similar to `read-string', but
                            '((window-height . fit-window-to-buffer)))
               (lambda (window _value)
                 (with-selected-window window
-                  (unwind-protect (and (y-or-n-p prompt-n) items)
+                  (unwind-protect (and (magit-y-or-n-p prompt-n) items)
                     (when (window-live-p window)
                       (quit-restore-window window 'kill)))))
               (dolist (item items)