Don't share options with a reference type column

Sharing `options` causes some unexpected behavior. If `limit: 2` is
specified, this means that 2 bytes integer for a reference id column and
2 chars string for a reference type column. Another example, if
`unsigned: true` is specified, this means that unsigned integer for a
reference id column, but a invalid option for a reference type column.
So `options` should not be shared with a reference type column.

(cherry picked from commit 465357aecf)

activerecord/CHANGELOG.md

@@ -1,3 +1,13 @@
+*   Don't share options between reference id and type columns
+
+    When using a polymorphic reference column in a migration, sharing options
+    between the two columns doesn't make sense since they are different types.
+    The `reference_id` column is usually an integer and the `reference_type`
+    column a string so options like `unsigned: true` will result in an invalid
+    table definition.
+
+    *Ryuta Kamizono*
+
 *   Fix regression of #1969 with SELECT aliases in HAVING clause.
 
     *Eugene Kenny*

activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

@@ -107,16 +107,12 @@ module ActiveRecord
 
       private
 
-      def as_options(value, default = {})
+      def as_options(value)
-        if value.is_a?(Hash)
+        value.is_a?(Hash) ? value : {}
-          value
-        else
-          default
-        end
       end
 
       def polymorphic_options
-        as_options(polymorphic, options)
+        as_options(polymorphic)
       end
 
       def index_options

activerecord/test/cases/migration/references_statements_test.rb

@@ -50,6 +50,13 @@ module ActiveRecord
         assert column_exists?(table_name, :taggable_type, :string, default: 'Photo')
       end
 
+      def test_does_not_share_options_with_reference_type_column
+        add_reference table_name, :taggable, type: :integer, limit: 2, polymorphic: true
+        assert column_exists?(table_name, :taggable_id, :integer, limit: 2)
+        assert column_exists?(table_name, :taggable_type, :string)
+        assert_not column_exists?(table_name, :taggable_type, :string, limit: 2)
+      end
+
       def test_creates_named_index
         add_reference table_name, :tag, index: { name: 'index_taggings_on_tag_id' }
         assert index_exists?(table_name, :tag_id, name: 'index_taggings_on_tag_id')