Fixed #30636 -- Fixed options ordering when cloning test database on MySQL.

--defaults-file must be given before other options.

django/db/backends/mysql/creation.py

@@ -56,8 +56,7 @@ class DatabaseCreation(BaseDatabaseCreation):
 
     def _clone_db(self, source_database_name, target_database_name):
         dump_args = DatabaseClient.settings_to_cmd_args(self.connection.settings_dict)[1:]
-        dump_args[-1] = source_database_name
-        dump_cmd = ['mysqldump', '--routines', '--events'] + dump_args
+        dump_cmd = ['mysqldump', *dump_args[:-1], '--routines', '--events', source_database_name]
         load_cmd = DatabaseClient.settings_to_cmd_args(self.connection.settings_dict)
         load_cmd[-1] = target_database_name
 

tests/backends/mysql/test_creation.py

@@ -1,3 +1,4 @@
+import subprocess
 import unittest
 from io import StringIO
 from unittest import mock
@@ -50,3 +51,35 @@ class DatabaseCreationTests(SimpleTestCase):
             with mock.patch.object(DatabaseCreation, '_clone_db') as _clone_db:
                 creation._clone_test_db('suffix', verbosity=0, keepdb=True)
                 _clone_db.assert_not_called()
+
+    def test_clone_test_db_options_ordering(self):
+        creation = DatabaseCreation(connection)
+        try:
+            saved_settings = connection.settings_dict
+            connection.settings_dict = {
+                'NAME': 'source_db',
+                'USER': '',
+                'PASSWORD': '',
+                'PORT': '',
+                'HOST': '',
+                'ENGINE': 'django.db.backends.mysql',
+                'OPTIONS': {
+                    'read_default_file': 'my.cnf',
+                },
+            }
+            with mock.patch.object(subprocess, 'Popen') as mocked_popen:
+                creation._clone_db('source_db', 'target_db')
+                mocked_popen.assert_has_calls([
+                    mock.call(
+                        [
+                            'mysqldump',
+                            '--defaults-file=my.cnf',
+                            '--routines',
+                            '--events',
+                            'source_db',
+                        ],
+                        stdout=subprocess.PIPE,
+                    ),
+                ])
+        finally:
+            connection.settings_dict = saved_settings