From 61d4d738e1f56fef1fd0ee00e5ff2047b8e03ea0 Mon Sep 17 00:00:00 2001
From: Santiago Pastorino <santiago@wyeworks.com>
Date: Tue, 26 Jul 2016 14:14:41 -0300
Subject: [PATCH] Merge pull request #25912 from
 stevenharman/fix_render_partial_collection_to_allow_custom_collection

Changed partial rendering to allow collections which don't implement `#to_ary`.
---
 actionview/CHANGELOG.md                               | 11 +++++++++++
 .../lib/action_view/renderer/partial_renderer.rb      |  2 +-
 actionview/test/template/render_test.rb               |  8 ++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/actionview/CHANGELOG.md b/actionview/CHANGELOG.md
index ba030f3fe1b15..0978ef8b98840 100644
--- a/actionview/CHANGELOG.md
+++ b/actionview/CHANGELOG.md
@@ -1,5 +1,16 @@
 ## Rails 5.0.0 (June 30, 2016) ##
 
+*   Changed partial rendering with a collection to allow collections which
+    implement `to_a`.
+
+    Extracting the collection option had an optimization to avoid unnecessary
+    queries of ActiveRecord Relations by calling `#to_ary` on the given
+    collection. Instances of `Enumerator` or `Enumerable` are valid
+    collections, but they do not implement `#to_ary`. By changing this to
+    `#to_a`, they will now be extracted and rendered as expected.
+
+    *Steven Harman*
+
 *   Change `datetime_field` and `datetime_field_tag` to generate `datetime-local` fields.
 
     As a new specification of the HTML 5 the text field type `datetime` will no longer exist
diff --git a/actionview/lib/action_view/renderer/partial_renderer.rb b/actionview/lib/action_view/renderer/partial_renderer.rb
index 13b4ec6133a19..398d961fff00d 100644
--- a/actionview/lib/action_view/renderer/partial_renderer.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer.rb
@@ -403,7 +403,7 @@ def setup(context, options, block)
     def collection_from_options
       if @options.key?(:collection)
         collection = @options[:collection]
-        collection.respond_to?(:to_ary) ? collection.to_ary : []
+        collection ? collection.to_a : []
       end
     end
 
diff --git a/actionview/test/template/render_test.rb b/actionview/test/template/render_test.rb
index 25b21850b15ec..68574d4adb721 100644
--- a/actionview/test/template/render_test.rb
+++ b/actionview/test/template/render_test.rb
@@ -309,6 +309,14 @@ def test_render_partial_with_nil_collection_should_return_nil
     assert_nil @view.render(:partial => "test/customer", :collection => nil)
   end
 
+  def test_render_partial_collection_for_non_array
+    customers = Enumerator.new do |y|
+      y.yield(Customer.new("david"))
+      y.yield(Customer.new("mary"))
+    end
+    assert_equal "Hello: davidHello: mary", @view.render(partial: "test/customer", collection: customers)
+  end
+
   def test_render_partial_without_object_does_not_put_partial_name_to_local_assigns
     assert_equal 'false', @view.render(partial: 'test/partial_name_in_local_assigns')
   end