Change env var delimiter to match non-word

If I pass an expression like: "$PWD/deps/local/lib" in the port env
string, it expands to "/deps/local/lib", (variable is expanded to the
empty string) but if I pass "${PWD}/deps/local/lib" it expands
properly. I found that confusing.

This was because we require environment vars to end with whitespace,
while I think requiring a non-word character would be sufficient, since
the variables can only contain word characters.

This changes the expansion system to recognize variables that are
terminated by non word characters.

This includes some fixes as per some comments by tuncer.

Fixes rebar/rebar#457

THANKS

@@ -133,3 +133,4 @@ Vlad Dumitrescu
 stwind
 Pavel Baturko
 Igor Savchuk
+Mark Anderson

src/rebar_utils.erl

@@ -254,8 +254,8 @@ expand_env_variable(InStr, VarName, RawVarValue) ->
             ReOpts = [global, unicode, {return, list}],
             VarValue = re:replace(RawVarValue, "\\\\", "\\\\\\\\", ReOpts),
             %% Use a regex to match/replace:
-            %% Given variable "FOO": match $FOO\s | $FOOeol | ${FOO}
+            %% Given variable "FOO", match $FOO\W | $FOOeol | ${FOO}.
-            RegEx = io_lib:format("\\\$(~s(\\s|$)|{~s})", [VarName, VarName]),
+            RegEx = io_lib:format("\\\$(~s(\\W|$)|{~s})", [VarName, VarName]),
             re:replace(InStr, RegEx, [VarValue, "\\2"], ReOpts)
     end.
 

test/rebar_utils_tests.erl

@@ -0,0 +1,50 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2015 Mark Anderson <mark@chef.io>
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -------------------------------------------------------------------
+%% @author Mark Anderson <mark@chef.io>
+%% @doc Tests functionality of rebar_utils module.
+%% @copyright 2015 Mark Anderson
+%% -------------------------------------------------------------------
+-module(rebar_utils_tests).
+
+-compile(export_all).
+
+-include_lib("eunit/include/eunit.hrl").
+
+expand_env_variable_test_() ->
+    [{"Ensure that variable expansion handles nonwhitespace",
+      fun() ->
+              Test = "$V $V/ $Vw",
+              ?assertEqual("Val Val/ $Vw",
+                           rebar_utils:expand_env_variable(Test, "V", "Val") )
+      end},
+     {"Ensure that variable expansion with braces works",
+      fun() ->
+              Test = "${V} ${V}/ ${V}w ${Vw}",
+              ?assertEqual("Val Val/ Valw ${Vw}",
+                           rebar_utils:expand_env_variable(Test, "V", "Val") )
+      end}].
+