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
This commit is contained in:
Russell Keith-Magee 2011-09-10 18:58:30 +00:00
parent 161c6328a0
commit fcee0c1b66
2 changed files with 10 additions and 15 deletions

View File

@ -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:

View File

@ -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>']