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Refs #27985 -- Reallowed using __exact=None as an alias for __isnull=True if a custom lookup class with lookup_name != None is registered as the exact lookup. 

Regression in 58da81a5a3 and prerequisite
for refs #28896.
This commit is contained in:
Sergey Fedoseev 2017-12-06 15:58:02 +05:00 committed by Tim Graham
parent 7c7bc6391a
commit 10bfa876be
2 changed files with 27 additions and 9 deletions
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19
django/db/models/sql/query.py
View File

@ -1068,23 +1068,24 @@ class Query:
lhs = self.try_transform(lhs, name)
# First try get_lookup() so that the lookup takes precedence if the lhs
# supports both transform and lookup for the name.
lookup_class = lhs.get_lookup(lookups[-1])
lookup_name = lookups[-1]
lookup_class = lhs.get_lookup(lookup_name)
if not lookup_class:
if lhs.field.is_relation:
raise FieldError('Related Field got invalid lookup: {}'.format(lookups[-1]))
raise FieldError('Related Field got invalid lookup: {}'.format(lookup_name))
# A lookup wasn't found. Try to interpret the name as a transform
# and do an Exact lookup against it.
lhs = self.try_transform(lhs, lookups[-1])
lookup_class = lhs.get_lookup('exact')
if not lookup_class:
return
lhs = self.try_transform(lhs, lookup_name)
lookup_name = 'exact'
lookup_class = lhs.get_lookup(lookup_name)
if not lookup_class:
return
lookup = lookup_class(lhs, rhs)
# Interpret '__exact=None' as the sql 'is NULL'; otherwise, reject all
# uses of None as a query value.
if lookup.rhs is None:
if lookup.lookup_name not in ('exact', 'iexact'):
if lookup_name not in ('exact', 'iexact'):
raise ValueError("Cannot use None as a query value")
return lhs.get_lookup('isnull')(lhs, True)
@ -1093,7 +1094,7 @@ class Query:
# DEFAULT_DB_ALIAS isn't nice but it's the best that can be done here.
# A similar thing is done in is_nullable(), too.
if (connections[DEFAULT_DB_ALIAS].features.interprets_empty_strings_as_nulls and
lookup.lookup_name == 'exact' and lookup.rhs == ''):
lookup_name == 'exact' and lookup.rhs == ''):
return lhs.get_lookup('isnull')(lhs, True)
return lookup

17
tests/custom_lookups/tests.py
View File

@ -240,6 +240,23 @@ class LookupTests(TestCase):
models.DateField._unregister_lookup(YearTransform)
models.DateField._unregister_lookup(YearTransform, custom_transform_name)
def test_custom_exact_lookup_none_rhs(self):
"""
__exact=None is transformed to __isnull=True if a custom lookup class
with lookup_name != 'exact' is registered as the `exact` lookup.
"""
class CustomExactLookup(models.Lookup):
lookup_name = 'somecustomlookup'
field = Author._meta.get_field('birthdate')
OldExactLookup = field.get_lookup('exact')
author = Author.objects.create(name='author', birthdate=None)
try:
type(field).register_lookup(Exactly, 'exact')
self.assertEqual(Author.objects.get(birthdate__exact=None), author)
finally:
type(field).register_lookup(OldExactLookup, 'exact')
def test_basic_lookup(self):
a1 = Author.objects.create(name='a1', age=1)
a2 = Author.objects.create(name='a2', age=2)