Fix #1811: take limit_choices_to into account with FK

rest_framework/relations.py

@@ -169,6 +169,12 @@ def get_queryset(self):
             # for the field.
             # Eg: 'MyRelationship(queryset=ExampleModel.objects.all())'
             queryset = queryset.all()
+        if hasattr(self.parent, "Meta") and hasattr(self.parent.Meta, "model"):
+            queryset = queryset.filter(
+                **self.parent.Meta.model._meta.get_field(
+                    self.source
+                ).get_limit_choices_to()
+            )
         return queryset
 
     def use_pk_only_optimization(self):

tests/models.py

@@ -52,6 +52,13 @@ class ForeignKeySource(RESTFrameworkModel):
                                on_delete=models.CASCADE)
 
 
+class ForeignKeySourceWithLimitedChoices(RESTFrameworkModel):
+    target = models.ForeignKey(ForeignKeyTarget, help_text='Target',
+                               verbose_name='Target',
+                               limit_choices_to={"name__startswith": "limited-"},
+                               on_delete=models.CASCADE)
+
+
 # Nullable ForeignKey
 class NullableForeignKeySource(RESTFrameworkModel):
     name = models.CharField(max_length=100)

tests/test_relations_with_limited_queryset.py

@@ -0,0 +1,38 @@
+from django.test import TestCase
+
+from rest_framework import serializers
+
+from .models import (
+    ForeignKeySource,
+    ForeignKeyTarget,
+    ForeignKeySourceWithLimitedChoices,
+)
+
+
+class ForeignKeySourceWithLimitedChoicesSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ForeignKeySourceWithLimitedChoices
+        fields = ("id", "target")
+
+
+class ForeignKeySourceSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ForeignKeySource
+        fields = ("id", "target")
+
+
+class LimitedChoicesInQuerySetTests(TestCase):
+    def setUp(self):
+        for idx in range(1, 4):
+            limited_target = ForeignKeyTarget(name="limited-target-%d" % idx)
+            limited_target.save()
+            target = ForeignKeyTarget(name="target-%d" % idx)
+            target.save()
+
+    def test_queryset_size_without_limited_choices(self):
+        queryset = ForeignKeySourceSerializer().fields["target"].get_queryset()
+        assert len(queryset) == 6
+
+    def test_queryset_size_with_limited_choices(self):
+        queryset = ForeignKeySourceWithLimitedChoicesSerializer().fields["target"].get_queryset()
+        assert len(queryset) == 3