bug#24725: 25.1.50; vc-region-history may exceed max line number of file in repository

[Tino Calancha <tino.calancha@gmail.com>]

emacs -Q lisp/vc/vc.el
C-x h
M-x vc-region-history RET
fatal: file vc.el has only 2921 lines
;; vc.el has 2922 lines but Git ignores the last empty line.

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From 12a6fc588fe60ebf98443a0fd068fe77d63bd17e Mon Sep 17 00:00:00 2001
From: Tino Calancha <tino.calancha@gmail.com>
Date: Tue, 18 Oct 2016 23:20:07 +0900
Subject: [PATCH] vc-region-history: Do not exceed the file maximum line number

The last empty line in a file is not part of the Git repository.
* lisp/vc/vc.el (vc-region-history): Exclude the last empty line
from the region (Bug#24724).
---
 lisp/vc/vc-git.el | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lisp/vc/vc-git.el b/lisp/vc/vc-git.el
index 9eac5b2..762f6af 100644
--- a/lisp/vc/vc-git.el
+++ b/lisp/vc/vc-git.el
@@ -1016,6 +1016,8 @@ vc-git-region-history
   ;; FIXME: Maybe this should be done in vc.el (i.e. for all backends), but
   ;; since Git is the only backend to support this operation so far, it's hard
   ;; to tell.
+  (when (> lto (1- (line-number-at-pos (point-max))))
+    (setq lto (1- (line-number-at-pos (point-max)))))
   (with-temp-buffer
     (vc-call-backend 'git 'diff file "HEAD" nil (current-buffer))
     (goto-char (point-min))
-- 
2.9.3

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In GNU Emacs 25.1.50.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.1)
 of 2016-10-13 built on calancha-pc
Repository revision: baa8ba4ed471d7fe4bb07c80a9dd16c4712525b4