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Fixed #30757 -- Added a system check to ensure max_length fits the longest choice.

This commit is contained in:
Nick Pope 2019-09-04 09:21:08 +01:00 committed by Mariusz Felisiak
parent fee75d2aed
commit b6251956b6
3 changed files with 45 additions and 0 deletions

View File

@ -257,6 +257,7 @@ class Field(RegisterLookupMixin):
)
]
choice_max_length = 0
# Expect [group_name, [value, display]]
for choices_group in self.choices:
try:
@ -270,16 +271,32 @@ class Field(RegisterLookupMixin):
for value, human_name in group_choices
):
break
if self.max_length is not None and group_choices:
choice_max_length = max(
choice_max_length,
*(len(value) for value, _ in group_choices if isinstance(value, str)),
)
except (TypeError, ValueError):
# No groups, choices in the form [value, display]
value, human_name = group_name, group_choices
if not is_value(value) or not is_value(human_name):
break
if self.max_length is not None and isinstance(value, str):
choice_max_length = max(choice_max_length, len(value))
# Special case: choices=['ab']
if isinstance(choices_group, str):
break
else:
if self.max_length is not None and choice_max_length > self.max_length:
return [
checks.Error(
"'max_length' is too small to fit the longest value "
"in 'choices' (%d characters)." % choice_max_length,
obj=self,
id='fields.E009',
),
]
return []
return [

View File

@ -138,6 +138,8 @@ Model fields
* **fields.E006**: ``db_index`` must be ``None``, ``True`` or ``False``.
* **fields.E007**: Primary keys must not have ``null=True``.
* **fields.E008**: All ``validators`` must be callable.
* **fields.E009**: ``max_length`` is too small to fit the longest value in
``choices`` (``<count>`` characters).
* **fields.E100**: ``AutoField``\s must set primary_key=True.
* **fields.E110**: ``BooleanField``\s do not accept null values. *This check
appeared before support for null values was added in Django 2.1.*

View File

@ -304,6 +304,32 @@ class CharFieldTests(SimpleTestCase):
self.assertEqual(Model._meta.get_field('field').check(), [])
def test_choices_in_max_length(self):
class Model(models.Model):
field = models.CharField(
max_length=2, choices=[
('ABC', 'Value Too Long!'), ('OK', 'Good')
],
)
group = models.CharField(
max_length=2, choices=[
('Nested', [('OK', 'Good'), ('Longer', 'Longer')]),
('Grouped', [('Bad', 'Bad')]),
],
)
for name, choice_max_length in (('field', 3), ('group', 6)):
with self.subTest(name):
field = Model._meta.get_field(name)
self.assertEqual(field.check(), [
Error(
"'max_length' is too small to fit the longest value "
"in 'choices' (%d characters)." % choice_max_length,
obj=field,
id='fields.E009',
),
])
def test_bad_db_index_value(self):
class Model(models.Model):
field = models.CharField(max_length=10, db_index='bad')