fix regression when loading fixture files with symbol keys.

Closes #22584.

activerecord/CHANGELOG.md

+*   Fix regression when loading fixture files with symbol keys.
+
+    Closes #22584.
+
+    *Yves Senn*
+
 *   Support `:if` and `:unless` options in `has_secure_token`
 
     *Griffin Smith*

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

@@ -297,14 +297,15 @@ def reset_sequence!(table, column, sequence = nil)
       # Inserts the given fixture into the table. Overridden in adapters that require
       # something beyond a simple insert (eg. Oracle).
       def insert_fixture(fixture, table_name)
-        columns = schema_cache.columns_hash(table_name)
+        fixture = fixture.stringify_keys
 
+        columns = schema_cache.columns_hash(table_name)
         binds = fixture.map do |name, value|
           if column = columns[name]
             type = lookup_cast_type_from_column(column)
             Relation::QueryAttribute.new(name, value, type)
           else
-            raise Fixture::FixtureError, %(table "#{table_name}" has no column named "#{name}".)
+            raise Fixture::FixtureError, %(table "#{table_name}" has no column named #{name.inspect}.)
           end
         end
         key_list = fixture.keys.map { |name| quote_column_name(name) }

activerecord/test/cases/fixtures_test.rb

@@ -223,6 +223,10 @@ def test_yaml_file_with_invalid_column
     assert_equal(%(table "parrots" has no column named "arrr".), e.message)
   end
 
+  def test_yaml_file_with_symbol_columns
+    ActiveRecord::FixtureSet.create_fixtures(FIXTURES_ROOT + "/naked/yml", "trees")
+  end
+
   def test_omap_fixtures
     assert_nothing_raised do
       fixtures = ActiveRecord::FixtureSet.new(Account.connection, 'categories', Category, FIXTURES_ROOT + "/categories_ordered")

activerecord/test/fixtures/naked/yml/trees.yml

+root:
+  :id: 1
+  :name: The Root