Merge pull request rails#11496 from jetthoughts/11376_has_many_assoc_respect_scope_on_build

Removed where_values_hash from AR::NullRelation
Conflicts:
	activerecord/CHANGELOG.md

Author: rafaelfranca

activerecord/CHANGELOG.md

@@ -1,5 +1,12 @@
 ## unreleased ##
 
+*   Objects intiantiated using a null relationship will now retain the
+    attributes of the where clause.
+
+    Fixes:  #11676, #11675, #11376
+
+    *Paul Nikitochkin*, *Peter Brown*, *Nthalk*
+
 *   Fixed `ActiveRecord::Associations::CollectionAssociation#find`
     when using `has_many` association with `:inverse_of` and finding an array of one element,
     it should return an array of one element too.

activerecord/lib/active_record/null_relation.rb

@@ -42,10 +42,6 @@ def to_sql
       @to_sql ||= ""
     end
 
-    def where_values_hash
-      {}
-    end
-
     def count(*)
       0
     end

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -135,6 +135,13 @@ def test_create_from_association_should_respect_default_scope
     assert_equal 'exotic', bulb.name
   end
 
+  def test_build_from_association_should_respect_scope
+    author = Author.new
+
+    post = author.thinking_posts.build
+    assert_equal 'So I was thinking', post.title
+  end
+
   def test_create_from_association_with_nil_values_should_work
     car = Car.create(:name => 'honda')
 
@@ -1702,6 +1709,22 @@ def test_association_attributes_are_available_to_after_initialize
     assert_equal car.id, bulb.attributes_after_initialize['car_id']
   end
 
+  def test_attributes_are_set_when_initialized_from_has_many_null_relationship
+    car  = Car.new name: 'honda'
+    bulb = car.bulbs.where(name: 'headlight').first_or_initialize
+    assert_equal 'headlight', bulb.name
+  end
+
+  def test_attributes_are_set_when_initialized_from_polymorphic_has_many_null_relationship
+    post    = Post.new title: 'title', body: 'bar'
+    tag     = Tag.create!(name: 'foo')
+
+    tagging = post.taggings.where(tag: tag).first_or_initialize
+
+    assert_equal tag.id, tagging.tag_id
+    assert_equal 'Post', tagging.taggable_type
+  end
+
   def test_replace
     car = Car.create(:name => 'honda')
     bulb1 = car.bulbs.create

activerecord/test/cases/relations_test.rb

@@ -295,6 +295,10 @@ def test_null_relation_metadata_methods
     assert_equal({}, Developer.none.where_values_hash)
   end
 
+  def test_null_relation_where_values_hash
+    assert_equal({ 'salary' => 100_000 }, Developer.none.where(salary: 100_000).where_values_hash)
+  end
+
   def test_joins_with_nil_argument
     assert_nothing_raised { DependentFirm.joins(nil).first }
   end