Commit fcee0c1b authored by Russell Keith-Magee's avatar Russell Keith-Magee
Browse files

Fixed #16809 -- Forced MySQL to behave like a database. This avoids a problem... 

Fixed #16809 -- Forced MySQL to behave like a database. This avoids a problem where queries that do IS NONE checks can return the wrong result the first time they are executed if there is a recently inserted row. Thanks to James Pyrich for the debug work and patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16785 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent 161c6328

django/db/backends/mysql/base.py

+10 −2
Original line number Diff line number Diff line
@@ -309,7 +309,9 @@ class DatabaseWrapper(BaseDatabaseWrapper): 
        return False



    def _cursor(self):

        new_connection = False

        if not self._valid_connection():

            new_connection = True

            kwargs = {

                'conv': django_conversions,

                'charset': 'utf8',
@@ -336,8 +338,14 @@ class DatabaseWrapper(BaseDatabaseWrapper): 
            self.connection.encoders[SafeUnicode] = self.connection.encoders[unicode]

            self.connection.encoders[SafeString] = self.connection.encoders[str]

            connection_created.send(sender=self.__class__, connection=self)

        cursor = CursorWrapper(self.connection.cursor())

        return cursor

        cursor = self.connection.cursor()

        if new_connection:

            # SQL_AUTO_IS_NULL in MySQL controls whether an AUTO_INCREMENT column

            # on a recently-inserted row will return when the field is tested for

            # NULL.  Disabling this value brings this aspect of MySQL in line with

            # SQL standards.

            cursor.execute('SET SQL_AUTO_IS_NULL = 0')

        return CursorWrapper(cursor)



    def _rollback(self):

        try:

tests/regressiontests/queries/tests.py

+0 −13
Original line number Diff line number Diff line
@@ -1070,10 +1070,6 @@ class Queries4Tests(BaseQuerysetTest): 
        ci3 = CategoryItem.objects.create(category=c3)



        qs = CategoryItem.objects.exclude(category__specialcategory__isnull=False)

        # Under MySQL, this query gives incorrect values on the first attempt.

        # If you run exactly the same query twice, it yields the right answer

        # the second attempt. Oh, how we do love MySQL.

        qs.count()

        self.assertEqual(qs.count(), 1)

        self.assertQuerysetEqual(qs, [ci1.pk], lambda x: x.pk)
@@ -1136,10 +1132,6 @@ class Queries4Tests(BaseQuerysetTest): 
        ci3 = CategoryItem.objects.create(category=c1)



        qs = CategoryItem.objects.exclude(category__onetoonecategory__isnull=False)

        # Under MySQL, this query gives incorrect values on the first attempt.

        # If you run exactly the same query twice, it yields the right answer

        # the second attempt. Oh, how we do love MySQL.

        qs.count()

        self.assertEqual(qs.count(), 1)

        self.assertQuerysetEqual(qs, [ci1.pk], lambda x: x.pk)
@@ -1421,11 +1413,6 @@ class Queries6Tests(TestCase): 
            []

        )



        # This next makes exactly *zero* sense, but it works. It's needed

        # because MySQL fails to give the right results the first time this

        # query is executed. If you run the same query a second time, it

        # works fine. It's a hack, but it works...

        list(Tag.objects.exclude(children=None))

        self.assertQuerysetEqual(

            Tag.objects.exclude(children=None),

            ['<Tag: t1>', '<Tag: t3>']