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Code Issues 25 Releases Wiki Activity

Fixed #24146 -- Fixed a missing fields regression in admin checks.

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This allows using get_field() early in the app loading process.

Thanks to PirosB3 and Tim Graham.
This commit is contained in:
Collin Anderson 2015-01-14 13:29:56 -05:00 committed by Tim Graham
parent 8e8daf7c9b
commit e8171daf0c
2 changed files with 31 additions and 13 deletions
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30
django/db/models/options.py
View File

@ -487,6 +487,12 @@ class Options(object):
@cached_property
def fields_map(self):
return self._get_fields_map()
def _get_fields_map(self):
# Helper method to provide a way to access this without caching it.
# For example, admin checks run before the app cache is ready and we
# need to be able to lookup fields before we cache the final result.
res = {}
fields = self._get_fields(forward=False, include_hidden=True)
for field in fields:
@ -531,20 +537,26 @@ class Options(object):
return field
except KeyError:
# If the app registry is not ready, reverse fields are
# unavailable, therefore we throw a FieldDoesNotExist exception.
if not self.apps.ready:
raise FieldDoesNotExist(
"%s has no field named %r. The app cache isn't ready yet, "
"so if this is an auto-created related field, it won't "
"be available yet." % (self.object_name, field_name)
)
pass
try:
if m2m_in_kwargs:
# Previous API does not allow searching reverse fields.
raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, field_name))
# If the app registry is not ready, reverse fields are probably
# unavailable, but try anyway.
if not self.apps.ready:
try:
# Don't cache results
return self._get_fields_map()[field_name]
except KeyError:
raise FieldDoesNotExist(
"%s has no field named %r. The app cache isn't ready yet, "
"so if this is an auto-created related field, it might not "
"be available yet." % (self.object_name, field_name)
)
try:
# Retrieve field instance by name from cached or just-computed
# field map.
return self.fields_map[field_name]

16
tests/model_meta/tests.py
View File

@ -169,24 +169,30 @@ class GetFieldByNameTests(OptionsBaseTests):
self.assertEqual(field_info[1:], (None, True, False))
self.assertIsInstance(field_info[0], GenericRelation)
def test_get_fields_only_searches_forward_on_apps_not_ready(self):
def test_get_fields_when_apps_not_ready(self):
opts = Person._meta
# If apps registry is not ready, get_field() searches over only
# forward fields.
opts.apps.ready = False
# Clear cached data.
opts.__dict__.pop('fields_map', None)
try:
# 'data_abstract' is a forward field, and therefore will be found
self.assertTrue(opts.get_field('data_abstract'))
msg = (
"Person has no field named 'relating_baseperson'. The app "
"Person has no field named 'some_missing_field'. The app "
"cache isn't ready yet, so if this is an auto-created related "
"field, it won't be available yet."
"field, it might not be available yet."
)
# 'data_abstract' is a reverse field, and will raise an exception
with self.assertRaisesMessage(FieldDoesNotExist, msg):
opts.get_field('relating_baseperson')
opts.get_field('some_missing_field')
# Be sure it's not cached
self.assertNotIn('fields_map', opts.__dict__)
finally:
opts.apps.ready = True
# At this point searching a related field would cache fields_map
opts.get_field('relating_baseperson')
self.assertIn('fields_map', opts.__dict__)
class RelationTreeTests(TestCase):