Commit 1e5e2a47 authored by André Ericson's avatar André Ericson
Browse files

Fixed #22064 -- Add check for related_name 

Validates that related_name is a valid Python id or ends with a '+' and
it's not a keyword. Without a check it passed silently leading to
unpredictable problems.

Thanks Konrad Świat for the initial work.
parent 8c581ff3

django/db/models/fields/related.py

+21 −0
Original line number Diff line number Diff line
@@ -97,11 +97,32 @@ signals.class_prepared.connect(do_pending_lookups) 
class RelatedField(Field):

    def check(self, **kwargs):

        errors = super(RelatedField, self).check(**kwargs)

        errors.extend(self._check_related_name_is_valid())

        errors.extend(self._check_relation_model_exists())

        errors.extend(self._check_referencing_to_swapped_model())

        errors.extend(self._check_clashes())

        return errors



    def _check_related_name_is_valid(self):

        import re

        import keyword

        related_name = self.rel.related_name



        is_valid_id = (related_name and re.match('^[a-zA-Z_][a-zA-Z0-9_]*$', related_name)

                       and not keyword.iskeyword(related_name))

        if related_name and not (is_valid_id or related_name.endswith('+')):

            return [

                checks.Error(

                    "The name '%s' is invalid related_name for field %s.%s" %

                    (self.rel.related_name, self.model._meta.object_name,

                     self.name),

                    hint="Related name must be a valid Python identifier or end with a '+'",

                    obj=self,

                    id='fields.E306',

                )

            ]

        return []



    def _check_relation_model_exists(self):

        rel_is_missing = self.rel.to not in apps.get_models()

        rel_is_string = isinstance(self.rel.to, six.string_types)

docs/ref/checks.txt

+2 −0
Original line number Diff line number Diff line
@@ -117,6 +117,8 @@ Related Fields 
  ``<field name>``.

* **fields.E305**: Field name ``<field name>`` clashes with reverse query name

  for ``<field name>``.

* **fields.E306**: Related name must be a valid Python identifier or end with

  a ``'+'``.

* **fields.E310**: None of the fields ``<field1>``, ``<field2>``, ... on model

  ``<model>`` have a ``unique=True`` constraint.

* **fields.E311**: ``<model>`` must set ``unique=True`` because it is

tests/invalid_models_tests/test_relative_fields.py

+67 −0
Original line number Diff line number Diff line
@@ -546,6 +546,73 @@ class RelativeFieldTests(IsolatedModelsTestCase): 
            errors = field.check(from_model=Model)

            self.assertEqual(errors, [expected_error])



    def test_related_field_has_invalid_related_name(self):

        digit = 0

        illegal_non_alphanumeric = '!'

        whitespace = '\t'



        invalid_related_names = [

            '%s_begins_with_digit' % digit,

            '%s_begins_with_illegal_non_alphanumeric' % illegal_non_alphanumeric,

            '%s_begins_with_whitespace' % whitespace,

            'contains_%s_illegal_non_alphanumeric' % illegal_non_alphanumeric,

            'contains_%s_whitespace' % whitespace,

            'ends_with_with_illegal_non_alphanumeric_%s' % illegal_non_alphanumeric,

            'ends_with_whitespace_%s' % whitespace,

            # Python's keyword

            'with',

        ]



        class Parent(models.Model):

            pass



        for invalid_related_name in invalid_related_names:

            Child = type(str('Child_%s') % str(invalid_related_name), (models.Model,), {

                'parent': models.ForeignKey('Parent', related_name=invalid_related_name),

                '__module__': Parent.__module__,

            })



            field = Child._meta.get_field('parent')

            errors = Child.check()

            expected = [

                Error(

                    "The name '%s' is invalid related_name for field Child_%s.parent"

                    % (invalid_related_name, invalid_related_name),

                    hint="Related name must be a valid Python identifier or end with a '+'",

                    obj=field,

                    id='fields.E306',

                ),

            ]

            self.assertEqual(errors, expected)



    def test_related_field_has_valid_related_name(self):

        lowercase = 'a'

        uppercase = 'A'

        digit = 0



        related_names = [

            '%s_starts_with_lowercase' % lowercase,

            '%s_tarts_with_uppercase' % uppercase,

            '_starts_with_underscore',

            'contains_%s_digit' % digit,

            'ends_with_plus+',

            '_',

            '_+',

            '+',

        ]



        class Parent(models.Model):

            pass



        for related_name in related_names:

            Child = type(str('Child_%s') % str(related_name), (models.Model,), {

                'parent': models.ForeignKey('Parent', related_name=related_name),

                '__module__': Parent.__module__,

            })



            errors = Child.check()

            self.assertFalse(errors)





class AccessorClashTests(IsolatedModelsTestCase):