From 67544cdf13ed33264738dd74c8dc44e39be9d24f Mon Sep 17 00:00:00 2001
From: Anthony Persaud <persaud@modernistik.com>
Date: Thu, 10 Aug 2017 15:12:30 -0700
Subject: [PATCH] All array properties will return a default collection proxy
 if nil.

---
 Changes.md                                    |  1 +
 .../model/associations/collection_proxy.rb    |  2 +-
 lib/parse/model/core/properties.rb            |  6 +++++
 .../lib/parse/models/collection_proxy_test.rb | 25 +++++++++++++++++++
 4 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 test/lib/parse/models/collection_proxy_test.rb

diff --git a/Changes.md b/Changes.md
index 64d2e70..c56c58a 100644
--- a/Changes.md
+++ b/Changes.md
@@ -2,6 +2,7 @@
 
 ### 1.7.2
 - FIXED: first_or_create will now apply dirty tracking to newly created fields.
+- FIXED: Properties of :array type will always return a Parse::CollectionProxy if their internal value is nil. The object will not be marked dirty until something is added to the array.
 - NEW: `Parse::Model.autosave_on_create` has been removed in favor of `first_or_create!`.
 - FIXED: Encoding a Parse::Object into JSON will remove any values that are `nil`
 which were not explicitly changed to that value.
diff --git a/lib/parse/model/associations/collection_proxy.rb b/lib/parse/model/associations/collection_proxy.rb
index 42efadb..e018916 100644
--- a/lib/parse/model/associations/collection_proxy.rb
+++ b/lib/parse/model/associations/collection_proxy.rb
@@ -75,7 +75,7 @@ def loaded?
       # @param params [Object] method parameters
       # @return [Object] the return value from the forwarded method.
       def forward(method, params = nil)
-        return unless @delegate.present? && @delegate.respond_to?(method)
+        return unless @delegate && @delegate.respond_to?(method)
         params.nil? ? @delegate.send(method) : @delegate.send(method, params)
       end
 
diff --git a/lib/parse/model/core/properties.rb b/lib/parse/model/core/properties.rb
index 41a9cf0..4bd2bbc 100644
--- a/lib/parse/model/core/properties.rb
+++ b/lib/parse/model/core/properties.rb
@@ -300,6 +300,12 @@ def property(key, data_type = :string, **opts)
             # lets set the variable with the updated value
              instance_variable_set ivar, value
              send will_change_method
+          elsif value.nil? && data_type == :array
+            value = Parse::CollectionProxy.new [], delegate: self, key: key
+            instance_variable_set ivar, value
+            # don't send the notification yet until they actually add something
+            # which will be handled by the collection proxy.
+            # send will_change_method
           end
 
           # if the value is a String (like an iso8601 date) and the data type of
diff --git a/test/lib/parse/models/collection_proxy_test.rb b/test/lib/parse/models/collection_proxy_test.rb
new file mode 100644
index 0000000..6d0e368
--- /dev/null
+++ b/test/lib/parse/models/collection_proxy_test.rb
@@ -0,0 +1,25 @@
+require_relative '../../../test_helper'
+
+class MyCollectionTest < Parse::Object
+  property :list, :array
+end
+
+class TestCollectionProxy < Minitest::Test
+
+  def test_default_access
+    o = MyCollectionTest.new
+    assert_equal o.list, []
+    changes = o.changes
+    changes.delete("acl")
+
+    assert_equal changes, {}, "Make sure default proxy collection doesn't affect dirty tracking"
+    refute o.list_changed?, "Make sure it didn't affect will_change methods."
+    refute o.changed.include?("list")
+
+    o.list.add "something"
+    assert o.changed.include?("list"), "Verify it is now included in dirty tracking list."
+    assert o.list_changed?, "Make sure it dirty tracking was forwarded on change."
+
+  end
+
+end