From: Peter Lemenkov <lemenkov@gmail.com>
Date: Sun, 6 Mar 2016 01:25:36 +0300
Subject: [PATCH] Try shell variable VSN first

Try shell variable VSN first before substituting version placeholder in
app-file.

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>

diff --git a/src/rebar_utils.erl b/src/rebar_utils.erl
index 348d06d..47975cb 100644
--- a/src/rebar_utils.erl
+++ b/src/rebar_utils.erl
@@ -268,7 +268,7 @@ vcs_vsn(Config, Vsn, Dir) ->
     Cache = rebar_config:get_xconf(Config, vsn_cache),
     case dict:find(Key, Cache) of
         error ->
-            VsnString = vcs_vsn_1(Vsn, Dir),
+            VsnString = case os:getenv("VSN") of false -> vcs_vsn_1(Vsn, Dir); V -> V end,
             Cache1 = dict:store(Key, VsnString, Cache),
             Config1 = rebar_config:set_xconf(Config, vsn_cache, Cache1),
             {Config1, VsnString};