From 2455c4ede8d4ff6f0754977b548708eec08869eb Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Tue, 15 Sep 2015 18:29:39 +0200
Subject: [PATCH] patch 7.4.870 Problem:    May get into an invalid state when
 using getchar() in an             expression mapping. Solution:   Anticipate
 mod_mask to change. (idea by Yukihiro Nakadaira)

---
 src/getchar.c | 5 ++++-
 src/version.c | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/getchar.c b/src/getchar.c
index 87588a93ac..f4ec991b09 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -1630,13 +1630,16 @@ vgetc()
       last_recorded_len = 0;
       for (;;)			/* this is done twice if there are modifiers */
       {
+	int did_inc = FALSE;
+
 	if (mod_mask)		/* no mapping after modifier has been read */
 	{
 	    ++no_mapping;
 	    ++allow_keys;
+	    did_inc = TRUE;	/* mod_mask may change value */
 	}
 	c = vgetorpeek(TRUE);
-	if (mod_mask)
+	if (did_inc)
 	{
 	    --no_mapping;
 	    --allow_keys;
diff --git a/src/version.c b/src/version.c
index bc1e5550ca..0cb1fc62b5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    870,
 /**/
     869,
 /**/