Ensure that the foreign key gets set when doing record.create_association or...

Ensure that the foreign key gets set when doing record.create_association or record.create_association. Fixes #1960.

activerecord/lib/active_record/associations/singular_association.rb

@@ -18,11 +18,11 @@ def writer(record)
       end
 
       def create(attributes = {}, options = {}, &block)
-        build(attributes, options, &block).tap { |record| record.save }
+        create_record(attributes, options, &block)
       end
 
       def create!(attributes = {}, options = {}, &block)
-        build(attributes, options, &block).tap { |record| record.save! }
+        create_record(attributes, options, true, &block)
       end
 
       def build(attributes = {}, options = {})
@@ -50,6 +50,15 @@ def replace(record)
         def set_new_record(record)
           replace(record)
         end
+
+        def create_record(attributes, options, raise_error = false)
+          record = build_record(attributes, options)
+          yield(record) if block_given?
+          saved = record.save
+          set_new_record(record)
+          raise RecordInvalid.new(record) if !saved && raise_error
+          record
+        end
     end
   end
 end

activerecord/test/cases/associations/belongs_to_associations_test.rb

@@ -667,4 +667,18 @@ def test_create_bang_with_block
     firm = client.create_firm!{ |f| f.name = 'Agency Company' }
     assert_equal 'Agency Company', firm.name
   end
+
+  def test_should_set_foreign_key_on_create_association
+    client = Client.create! :name => "fuu"
+
+    firm = client.create_firm :name => "baa"
+    assert_equal firm.id, client.client_of
+  end
+
+  def test_should_set_foreign_key_on_create_association!
+    client = Client.create! :name => "fuu"
+
+    firm = client.create_firm! :name => "baa"
+    assert_equal firm.id, client.client_of
+  end
 end