From 4e3a2784ec3cb4ff79bd48f55a8edee817dec6e7 Mon Sep 17 00:00:00 2001
From: James McCoy <jamessan@jamessan.com>
Date: Mon, 6 Mar 2017 12:14:39 -0500
Subject: [PATCH] vim-patch:7.4.2068

Problem:    Not all arguments of trunc_string() are tested.  Memory access
            error when running the message tests.
Solution:   Add another test case. (Yegappan Lakshmanan)  Make it easy to run
            unittests with valgrind.  Fix the access error.

https://github.com/vim/vim/commit/b9644433d2728e99fab874e5e33147ad95d23a31
---
 src/nvim/message.c         |  4 ++--
 src/nvim/version.c         |  2 +-
 test/unit/message_spec.lua | 28 +++++++++++++++++++---------
 3 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/src/nvim/message.c b/src/nvim/message.c
index 57f7369e73..689e8893bd 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -274,9 +274,9 @@ void trunc_string(char_u *s, char_u *buf, int room, int buflen)
   for (;;) {
     do {
       half = half - (*mb_head_off)(s, s + half - 1) - 1;
-    } while (utf_iscomposing(utf_ptr2char(s + half)) && half > 0);
+    } while (half > 0 && utf_iscomposing(utf_ptr2char(s + half)));
     n = ptr2cells(s + half);
-    if (len + n > room) {
+    if (len + n > room || half == 0) {
       break;
     }
     len += n;
diff --git a/src/nvim/version.c b/src/nvim/version.c
index b755404a58..abd3b7dfc3 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -372,7 +372,7 @@ static int included_patches[] = {
   2071,
   // 2070 NA
   // 2069,
-  // 2068,
+  2068,
   2067,
   2066,
   2065,
diff --git a/test/unit/message_spec.lua b/test/unit/message_spec.lua
index 23d342c027..afb572347f 100644
--- a/test/unit/message_spec.lua
+++ b/test/unit/message_spec.lua
@@ -4,22 +4,28 @@ local ffi = helpers.ffi
 local eq = helpers.eq
 local to_cstr = helpers.to_cstr
 
-local cimp = helpers.cimport('./src/nvim/message.h')
+local cimp = helpers.cimport('./src/nvim/message.h', './src/nvim/memory.h',
+                             './src/nvim/strings.h')
 
 describe('trunc_string', function()
-  local buffer = ffi.typeof('char_u[40]')
-
-  local function test_inplace(s, expected)
-    local buf = buffer()
+  local buflen = 40
+  local function test_inplace(s, expected, room)
+    room = room and room or 20
+    local buf = cimp.xmalloc(ffi.sizeof('char_u') * buflen)
     ffi.C.strcpy(buf, s)
-    cimp.trunc_string(buf, buf, 20, 40)
+    cimp.trunc_string(buf, buf, room, buflen)
     eq(expected, ffi.string(buf))
+    cimp.xfree(buf)
   end
 
-  local function test_copy(s, expected)
-    local buf = buffer()
-    cimp.trunc_string(to_cstr(s), buf, 20, 40)
+  local function test_copy(s, expected, room)
+    room = room and room or 20
+    local buf = cimp.xmalloc(ffi.sizeof('char_u') * buflen)
+    local str = cimp.vim_strsave(to_cstr(s))
+    cimp.trunc_string(str, buf, room, buflen)
     eq(expected, ffi.string(buf))
+    cimp.xfree(buf)
+    cimp.xfree(str)
   end
 
   local permutations = {
@@ -37,6 +43,10 @@ describe('trunc_string', function()
         t.func('a short text', 'a short text')
       end)
 
+      it('with a string of length == 1/2 room', function()
+        t.func('a text that fits', 'a text that fits', 34)
+      end)
+
       it('with a string exactly the truncate size', function()
         t.func('a text tha just fits', 'a text tha just fits')
       end)