From 3ef1783b1a77c8ebfd43e4566de6a3b3d25c2584 Mon Sep 17 00:00:00 2001
From: Ryan <ryan.stewart@rackspace.com>
Date: Wed, 21 Dec 2016 11:35:15 -0600
Subject: [PATCH] fixes setting array syntax

Existing handling of setting array indexes has a couple of issues. First, it calls a non-existent lists:append/3 in a couple
of places. It also mishandles setting the first element of an array greater than length one. This adds tests that cover the
problem spots in the code and fixes the problems.
---
 src/props.erl        | 10 ++++------
 test/props_SUITE.erl | 28 ++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/src/props.erl b/src/props.erl
index aa55273..d754ae6 100644
--- a/src/props.erl
+++ b/src/props.erl
@@ -144,10 +144,8 @@ do_set([{prop, Key}], _Value, NonProps) ->
 do_set([{index, Idx}], Value, List) when is_list(List) ->
     try
         {Prefix, Suffix} = case {Idx, List} of
-                               {1, []} ->
-                                   {[], []};
-                               {1, [_ | Suf]} ->
-                                   {[], Suf};
+                               {1, _} ->
+                                   {[], List};
                                _ ->
                                    lists:split(Idx - 1, List)
                            end,
@@ -155,7 +153,7 @@ do_set([{index, Idx}], Value, List) when is_list(List) ->
             [] ->
                 lists:append(Prefix, [Value]);
             [_ | Rest] ->
-                lists:append(Prefix, [Value], Rest)
+                lists:append([Prefix, [Value], Rest])
         end
     catch
         _:_ ->
@@ -193,7 +191,7 @@ do_set([{index, Idx} | Rest], Value, List) when is_list(List) ->
             lists:append(Prefix, [[]]);
         {[OldVal | End], _} ->
             Val = do_set(Rest, Value, OldVal),
-            lists:append(Prefix, [Val], End)
+            lists:append([Prefix, [Val], End])
     end;
 do_set([{index, Idx} | _Rest], _Value, NonList) ->
     throw(?INVALID_ACCESS_IDX(Idx, NonList)).
diff --git a/test/props_SUITE.erl b/test/props_SUITE.erl
index 4f30731..4e62035 100644
--- a/test/props_SUITE.erl
+++ b/test/props_SUITE.erl
@@ -10,6 +10,10 @@
          simple_set/1,
          multi_set/1,
          array_index_change/1,
+         array_index_change_first/1,
+         array_index_change_middle/1,
+         array_index_change_last/1,
+         array_object_field_change/1,
          create_implicit_props/1,
          create_implicit_array/1,
          create_implicit_index/1,
@@ -65,6 +69,10 @@ all() ->
      simple_set,
      multi_set,
      array_index_change,
+     array_index_change_first,
+     array_index_change_middle,
+     array_index_change_last,
+     array_object_field_change,
      create_implicit_props,
      create_implicit_array,
      create_implicit_index,
@@ -119,6 +127,26 @@ array_index_change(_Config) ->
     Dst = {[{<<"a">>, [2]}]},
     Dst = props:set("a[1]", 2, Src).
 
+array_index_change_first(_Config) ->
+    Src = {[{<<"a">>, [1, 3, 5]}]},
+    Dst = {[{<<"a">>, [2, 3, 5]}]},
+    Dst = props:set("a[1]", 2, Src).
+
+array_index_change_middle(_Config) ->
+    Src = {[{<<"a">>, [1, 3, 5]}]},
+    Dst = {[{<<"a">>, [1, 2, 5]}]},
+    Dst = props:set("a[2]", 2, Src).
+
+array_index_change_last(_Config) ->
+    Src = {[{<<"a">>, [1, 3, 5]}]},
+    Dst = {[{<<"a">>, [1, 3, 2]}]},
+    Dst = props:set("a[3]", 2, Src).
+
+array_object_field_change(_Config) ->
+    Src = {[{<<"a">>, [{[{<<"b">>, 1}]}]}]},
+    Dst = {[{<<"a">>, [{[{<<"b">>, 2}]}]}]},
+    Dst = props:set("a[1].b", 2, Src).
+
 create_implicit_props(_Config) ->
     Src = {[]},
     Dst = {[{<<"a">>, {[{<<"b">>, 1}]}}]},