Infinite Recursion Fix

dynamic_rest/conf.py

@@ -72,6 +72,10 @@
     # Enables caching of serializer fields to speed up serializer usage
     # Needs to also be configured on a per-serializer basis
     'ENABLE_FIELDS_CACHE': False,
+
+    # Controls maximum recursion depth to prevent infinite recursion
+    # in cases where two DynamicRelationFields interfere with each other
+    MAX_RECURSION_DEPTH: 5
 }
 
 

dynamic_rest/filters.py

@@ -378,7 +378,8 @@ def _build_requested_prefetches(
         requirements,
         model,
         fields,
-        filters
+        filters,
+        recursion_depth=0
     ):
         """Build a prefetch dictionary based on request requirements."""
 
@@ -418,22 +419,24 @@ def _build_requested_prefetches(
             # not conflict.
             required = requirements.pop(source, None)
 
-            prefetch_queryset = self._build_queryset(
-                serializer=field,
-                filters=filters.get(name, {}),
-                queryset=related_queryset,
-                requirements=required
-            )
+            if recursion_depth < settings.MAX_RECURSION_DEPTH:
+                prefetch_queryset = self._build_queryset(
+                    serializer=field,
+                    filters=filters.get(name, {}),
+                    queryset=related_queryset,
+                    requirements=required,
+                    recursion_depth=recursion_depth + 1
+                )
 
-            # Note: There can only be one prefetch per source, even
-            #       though there can be multiple fields pointing to
-            #       the same source. This could break in some cases,
-            #       but is mostly an issue on writes when we use all
-            #       fields by default.
-            prefetches[source] = self._create_prefetch(
-                source,
-                prefetch_queryset
-            )
+                # Note: There can only be one prefetch per source, even
+                #       though there can be multiple fields pointing to
+                #       the same source. This could break in some cases,
+                #       but is mostly an issue on writes when we use all
+                #       fields by default.
+                prefetches[source] = self._create_prefetch(
+                    source,
+                    prefetch_queryset
+                )
 
         return prefetches
 
@@ -477,6 +480,7 @@ def _build_queryset(
         requirements=None,
         extra_filters=None,
         disable_prefetches=False,
+        recursion_depth=0,
     ):
         """Build a queryset that pulls in all data required by this request.
 
@@ -539,7 +543,8 @@ def _build_queryset(
             requirements,
             model,
             fields,
-            filters
+            filters,
+            recursion_depth=recursion_depth + 1
         )
 
         # build remaining prefetches out of internal requirements

tests/serializers.py

@@ -48,6 +48,24 @@ class Meta:
         untrimmed_fields = ('name',)
 
 
+class CatSerializer2(DynamicModelSerializer):
+    home = DynamicRelationField('LocationSerializer', link=None)
+    backup_home = DynamicRelationField(
+        'LocationSerializer', link=backup_home_link)
+    foobar = DynamicRelationField(
+        'LocationSerializer', source='hunting_grounds', many=True)
+    parent_id = DynamicRelationField('CatSerializer2', source='parent', read_only=True)
+    parent = DynamicRelationField('CatSerializer2', embed=True, deferred=True, read_only=True)
+
+    class Meta:
+        model = Cat
+        name = 'cat'
+        fields = ('id', 'name', 'home', 'backup_home', 'foobar', 'parent_id', 'parent')
+        deferred_fields = ('home', 'backup_home', 'foobar', 'parent')
+        immutable_fields = ('name',)
+        untrimmed_fields = ('name',)
+
+
 class LocationSerializer(DynamicModelSerializer):
 
     class Meta:

tests/settings.py

@@ -65,3 +65,5 @@
     'ENABLE_LINKS': True,
     'DEBUG': os.environ.get('DYNAMIC_REST_DEBUG', 'false').lower() == 'true'
 }
+
+MAX_RECURSION_DEPTH = 5

tests/test_recurse.py

@@ -0,0 +1,58 @@
+import datetime
+import json
+
+from django.db import connection
+from django.test import override_settings
+import six
+from rest_framework.test import APITestCase
+
+from tests.models import Cat, Group, Location, Permission, Profile, User
+from tests.serializers import NestedEphemeralSerializer, PermissionSerializer
+from tests.setup import create_fixture
+
+UNICODE_STRING = six.unichr(9629)  # unicode heart
+# UNICODE_URL_STRING = urllib.quote(UNICODE_STRING.encode('utf-8'))
+UNICODE_URL_STRING = '%E2%96%9D'
+
+
+@override_settings(
+    DYNAMIC_REST={
+        'ENABLE_LINKS': False
+    }
+)
+class Tests(APITestCase):
+
+    def setUp(self):
+        self.fixture = create_fixture()
+        home_id = self.fixture.locations[0].id
+        backup_home_id = self.fixture.locations[1].id
+        parent = Cat.objects.create(
+            name='Parent 1',
+            home_id=home_id,
+            backup_home_id=backup_home_id
+        )
+        self.kitten = Cat.objects.create(
+            name='Kitten 1',
+            home_id=home_id,
+            backup_home_id=backup_home_id,
+            parent=parent
+        )
+
+    def test_put(self):
+        parent_id = self.kitten.parent_id
+        kitten_name = 'Kitten 1'
+        data = {
+            'name': kitten_name,
+            'home': self.kitten.home_id,
+            'backup_home': self.kitten.backup_home_id,
+            'parent': parent_id
+        }
+        response = self.client.put(
+            f'/cats2/{self.kitten.id}',
+            json.dumps(data),
+            content_type='application/json'
+        )
+        self.assertEqual(200, response.status_code)
+        data = json.loads(response.content.decode('utf-8'))
+        self.assertEqual(data['cat']['parent']['id'], parent_id)
+        self.assertEqual(data['cat']['name'], kitten_name)

tests/urls.py

@@ -11,6 +11,7 @@
 
 router.register(r'cars', viewsets.CarViewSet)
 router.register(r'cats', viewsets.CatViewSet)
+router.register(r'cats2', viewsets.CatViewSet2)
 router.register_resource(viewsets.DogViewSet)
 router.register_resource(viewsets.HorseViewSet)
 router.register_resource(viewsets.PermissionViewSet)

tests/viewsets.py

@@ -16,6 +16,7 @@
 )
 from tests.serializers import (
     CarSerializer,
+    CatSerializer2,
     CatSerializer,
     DogSerializer,
     GroupSerializer,
@@ -147,6 +148,11 @@ class CatViewSet(DynamicModelViewSet):
     queryset = Cat.objects.all()
 
 
+class CatViewSet2(DynamicModelViewSet):
+    serializer_class = CatSerializer2
+    queryset = Cat.objects.all()
+
+
 class DogViewSet(DynamicModelViewSet):
     model = Dog
     serializer_class = DogSerializer