Fixed #16961 -- Skipped resetting AUTO_INCREMENT fields for MySQL if the server version is greater than 5.0.12. This allows for much faster testing.

Thanks to aigarius for the report and claudep and ramiro for review.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@17932 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/backends/mysql/base.py

@@ -261,15 +261,17 @@ class DatabaseOperations(BaseDatabaseOperations):
                 sql.append('%s %s;' % (style.SQL_KEYWORD('TRUNCATE'), style.SQL_FIELD(self.quote_name(table))))
             sql.append('SET FOREIGN_KEY_CHECKS = 1;')
 
-            # 'ALTER TABLE table AUTO_INCREMENT = 1;'... style SQL statements
-            # to reset sequence indices
-            sql.extend(["%s %s %s %s %s;" % \
-                (style.SQL_KEYWORD('ALTER'),
-                 style.SQL_KEYWORD('TABLE'),
-                 style.SQL_TABLE(self.quote_name(sequence['table'])),
-                 style.SQL_KEYWORD('AUTO_INCREMENT'),
-                 style.SQL_FIELD('= 1'),
-                ) for sequence in sequences])
+            # Truncate already resets the AUTO_INCREMENT field from
+            # MySQL version 5.0.13 onwards. Refs #16961.
+            if self.connection.mysql_version < (5,0,13):
+                sql.extend(
+                    ["%s %s %s %s %s;" % \
+                     (style.SQL_KEYWORD('ALTER'),
+                      style.SQL_KEYWORD('TABLE'),
+                      style.SQL_TABLE(self.quote_name(sequence['table'])),
+                      style.SQL_KEYWORD('AUTO_INCREMENT'),
+                      style.SQL_FIELD('= 1'),
+                     ) for sequence in sequences])
             return sql
         else:
             return []

tests/regressiontests/backends/tests.py

@@ -61,10 +61,34 @@ class OracleChecks(unittest.TestCase):
     def test_client_encoding(self):
         # If the backend is Oracle, test that the client encoding is set
         # correctly.  This was broken under Cygwin prior to r14781.
-        c = connection.cursor()  # Ensure the connection is initialized.
+        connection.cursor()  # Ensure the connection is initialized.
         self.assertEqual(connection.connection.encoding, "UTF-8")
         self.assertEqual(connection.connection.nencoding, "UTF-8")
 
+class MySQLTests(TestCase):
+    @unittest.skipUnless(connection.vendor == 'mysql',
+                        "Test valid only for MySQL")
+    def test_autoincrement(self):
+        """
+        Check that auto_increment fields are reset correctly by sql_flush().
+        Before MySQL version 5.0.13 TRUNCATE did not do auto_increment reset.
+        Refs #16961.
+        """
+        statements = connection.ops.sql_flush(no_style(),
+                                              tables=['test'],
+                                              sequences=[{
+                                                  'table': 'test',
+                                                  'col': 'somecol',
+                                              }])
+        found_reset = False
+        for sql in statements:
+            found_reset = found_reset or 'ALTER TABLE' in sql
+        if connection.mysql_version < (5,0,13):
+            self.assertTrue(found_reset)
+        else:
+            self.assertFalse(found_reset)
+
+
 class DateQuotingTest(TestCase):
 
     def test_django_date_trunc(self):

tests/regressiontests/test_runner/models.py

@@ -0,0 +1,5 @@
+from django.db import models
+
+class Person(models.Model):
+    first_name = models.CharField(max_length=20)
+    last_name = models.CharField(max_length=20)

tests/regressiontests/test_runner/tests.py

@@ -8,13 +8,15 @@ from optparse import make_option
 from django.core.exceptions import ImproperlyConfigured
 from django.core.management import call_command
 from django import db
-from django.test import simple
+from django.db import connection
+from django.test import simple, TransactionTestCase
 from django.test.simple import DjangoTestSuiteRunner, get_tests
 from django.test.testcases import connections_support_transactions
 from django.utils import unittest
 from django.utils.importlib import import_module
 
 from ..admin_scripts.tests import AdminScriptTestCase
+from .models import Person
 
 
 TEST_APP_OK = 'regressiontests.test_runner.valid_app.models'
@@ -281,3 +283,24 @@ class Sqlite3InMemoryTestDbs(unittest.TestCase):
                 self.assertTrue(connections_support_transactions(), msg)
             finally:
                 db.connections = old_db_connections
+
+
+class AutoIncrementResetTest(TransactionTestCase):
+    """
+    Here we test creating the same model two times in different test methods,
+    and check that both times they get "1" as their PK value. That is, we test
+    that AutoField values start from 1 for each transactional test case.
+    """
+    @unittest.skipIf(connection.vendor == 'oracle',
+                     "Oracle's auto-increment fields are not reset between "
+                     "tests")
+    def test_autoincrement_reset1(self):
+        p = Person.objects.create(first_name='Jack', last_name='Smith')
+        self.assertEquals(p.pk, 1)
+
+    @unittest.skipIf(connection.vendor == 'oracle',
+                     "Oracle's auto-increment fields are not reset between "
+                     "tests")
+    def test_autoincrement_reset2(self):
+        p = Person.objects.create(first_name='Jack', last_name='Smith')
+        self.assertEquals(p.pk, 1)