Commit 8bbdcc76 authored by Albert Wang's avatar Albert Wang Committed by Tim Graham
Browse files

Fixed #19299 -- Fixed Nullification of Foreign Keys To CharFields 

Thanks tunixman for the report and Baptiste Mispelon and
Shai Berger for reviews.
parent 4d4e0ea4

AUTHORS

+1 −0
Original line number Diff line number Diff line
@@ -646,6 +646,7 @@ answer newbie questions, and generally made Django that much better: 
    Rick Wagner <rwagner@physics.ucsd.edu>

    Gavin Wahl <gavinwahl@gmail.com>

    wam-djangobug@wamber.net

    Albert Wang <aywang31@gmail.com>

    Wang Chun <wangchun@exoweb.net>

    Filip Wasilewski <filip.wasilewski@gmail.com>

    Dan Watson <http://danwatson.net/>

django/db/models/fields/related.py

+4 −3
Original line number Diff line number Diff line
@@ -1692,11 +1692,12 @@ class ForeignKey(ForeignObject): 
        return field_default



    def get_db_prep_save(self, value, connection):

        if value == '' or value is None:

        if value is None or (value == '' and

                             (not self.related_field.empty_strings_allowed or

                              connection.features.interprets_empty_strings_as_nulls)):

            return None

        else:

            return self.related_field.get_db_prep_save(value,

                connection=connection)

            return self.related_field.get_db_prep_save(value, connection=connection)



    def value_to_string(self, obj):

        if not obj:

django/db/models/query.py

+5 −2
Original line number Diff line number Diff line
@@ -1416,9 +1416,12 @@ def get_cached_row(row, index_start, using, klass_info, offset=0, 
    klass, field_names, field_count, related_fields, reverse_related_fields, pk_idx = klass_info



    fields = row[index_start:index_start + field_count]

    # If the pk column is None (or the Oracle equivalent ''), then the related

    # If the pk column is None (or the equivalent '' in the case the

    # connection interprets empty strings as nulls), then the related

    # object must be non-existent - set the relation to None.

    if fields[pk_idx] is None or fields[pk_idx] == '':

    if (fields[pk_idx] is None or

        (connections[using].features.interprets_empty_strings_as_nulls and

         fields[pk_idx] == '')):

        obj = None

    elif field_names:

        fields = list(fields)

tests/model_fields/models.py

+9 −0
Original line number Diff line number Diff line
@@ -72,12 +72,21 @@ class BooleanModel(models.Model): 
    string = models.CharField(max_length=10, default='abc')





class PrimaryKeyCharModel(models.Model):

    string = models.CharField(max_length=10, primary_key=True)





class FksToBooleans(models.Model):

    """Model wih FKs to models with {Null,}BooleanField's, #15040"""

    bf = models.ForeignKey(BooleanModel)

    nbf = models.ForeignKey(NullBooleanModel)





class FkToChar(models.Model):

    """Model with FK to a model with a CharField primary key, #19299"""

    out = models.ForeignKey(PrimaryKeyCharModel)





class RenamedField(models.Model):

    modelname = models.IntegerField(name="fieldname", choices=((1, 'One'),))

tests/model_fields/tests.py

+13 −2
Original line number Diff line number Diff line
@@ -22,8 +22,8 @@ from django.utils.functional import lazy 


from .models import (

    Foo, Bar, Whiz, BigD, BigS, BigInt, Post, NullBooleanModel,

    BooleanModel, DataModel, Document, RenamedField,

    VerboseNameField, FksToBooleans)

    BooleanModel, PrimaryKeyCharModel, DataModel, Document, RenamedField,

    VerboseNameField, FksToBooleans, FkToChar)





class BasicFieldTests(test.TestCase):
@@ -146,6 +146,17 @@ class ForeignKeyTests(test.TestCase): 
        b = Bar.objects.create(b="bcd")

        self.assertEqual(b.a, a)



    @test.skipIfDBFeature('interprets_empty_strings_as_nulls')

    def test_empty_string_fk(self):

        """

        Test that foreign key values to empty strings don't get converted

        to None (#19299)

        """

        char_model_empty = PrimaryKeyCharModel.objects.create(string='')

        fk_model_empty = FkToChar.objects.create(out=char_model_empty)

        fk_model_empty = FkToChar.objects.select_related('out').get(id=fk_model_empty.pk)

        self.assertEqual(fk_model_empty.out, char_model_empty)





class DateTimeFieldTests(unittest.TestCase):

    def test_datetimefield_to_python_usecs(self):