diff-apply-buffer: Operate on region, add prefix argument

* lisp/vc/diff-mode.el (diff-apply-buffer): Interactively,
operate on an active region.  Reverse-apply hunks with a prefix
argument, like C-u C-c C-a already does.

(cherry picked from commit 942bb22c9f936a5f2f55dcf12748601ec4046deb)

diff --git a/lisp/vc/diff-mode.el b/lisp/vc/diff-mode.el
index 9f45c8eba723f52f33dc0c62e32679954aba8c4b..5db61b144b33b1412d69cbadd1d24524e7c2be0e 100644 (file)
--- a/lisp/vc/diff-mode.el
+++ b/lisp/vc/diff-mode.el
@@ -2202,12 +2202,18 @@ customize `diff-ask-before-revert-and-kill-hunk' to control that."
 
 (defun diff-apply-buffer (&optional beg end reverse)
   "Apply the diff in the entire diff buffer.
+Interactively, if the region is active, apply all hunks that the region
+overlaps; otherwise, apply all hunks.
+With a prefix argument, reverse-apply the hunks.
 If applying all hunks succeeds, save the changed buffers.
+
 When called from Lisp with optional arguments, restrict the application
-to hunks lying between BEG and END, and reverse-apply them when REVERSE is
-non-nil.  Returns nil if buffers were successfully modified and saved, or
-the number of failed hunk applications otherwise."
-  (interactive)
+to hunks lying between BEG and END, and reverse-apply them when REVERSE
+is non-nil.  Returns nil if buffers were successfully modified and
+saved, or the number of failed hunk applications otherwise."
+  (interactive (list (use-region-beginning)
+                     (use-region-end)
+                     current-prefix-arg))
   (let ((buffer-edits nil)
         (failures 0)
         (diff-refine nil))