Fixed #3871 -- Fixed regression introduced by 04a2a6b0.

Added do_not_call_in_templates=True attribute to RelatedManagers
to prevent them from being called.

Thanks jbg@ for the report.

django/contrib/contenttypes/generic.py

@@ -335,6 +335,7 @@ def create_generic_related_manager(superclass):
                 object_id_field_name = self.object_id_field_name,
                 prefetch_cache_name = self.prefetch_cache_name,
             )
+        do_not_call_in_templates = True
 
         def get_queryset(self):
             try:

django/db/models/fields/related.py

@@ -377,6 +377,7 @@ def create_foreign_related_manager(superclass, rel_field, rel_model):
             manager = getattr(self.model, kwargs.pop('manager'))
             manager_class = create_foreign_related_manager(manager.__class__, rel_field, rel_model)
             return manager_class(self.instance)
+        do_not_call_in_templates = True
 
         def get_queryset(self):
             try:
@@ -545,6 +546,7 @@ def create_many_related_manager(superclass, rel):
                 through=self.through,
                 prefetch_cache_name=self.prefetch_cache_name,
             )
+        do_not_call_in_templates = True
 
         def get_queryset(self):
             try:

tests/managers_regress/models.py

@@ -3,7 +3,9 @@ Various edge-cases for model managers.
 """
 
 from django.db import models
-from django.utils.encoding import python_2_unicode_compatible
+from django.contrib.contenttypes import generic
+from django.contrib.contenttypes.models import ContentType
+from django.utils.encoding import python_2_unicode_compatible, force_text
 
 
 class OnlyFred(models.Manager):
@@ -119,3 +121,26 @@ class Child6(Child4):
 # Will not inherit default manager from parent.
 class Child7(Parent):
     pass
+
+
+# RelatedManagers
+@python_2_unicode_compatible
+class RelatedModel(models.Model):
+    test_gfk = generic.GenericRelation('RelationModel', content_type_field='gfk_ctype', object_id_field='gfk_id')
+
+    def __str__(self):
+        return force_text(self.pk)
+
+
+@python_2_unicode_compatible
+class RelationModel(models.Model):
+    fk = models.ForeignKey(RelatedModel, related_name='test_fk')
+
+    m2m = models.ManyToManyField(RelatedModel, related_name='test_m2m')
+
+    gfk_ctype = models.ForeignKey(ContentType)
+    gfk_id = models.IntegerField()
+    gfk = generic.GenericForeignKey(ct_field='gfk_ctype', fk_field='gfk_id')
+
+    def __str__(self):
+        return force_text(self.pk)

tests/managers_regress/tests.py

@@ -4,8 +4,9 @@ import copy
 from django.conf import settings
 from django.db import models
 from django.db.models.loading import cache
+from django.template import Context, Template
 from django.test import TestCase
-from django.test.utils import override_settings
+from django.utils.encoding import force_text
 
 from .models import (
     Child1,
@@ -18,6 +19,8 @@ from .models import (
     AbstractBase1,
     AbstractBase2,
     AbstractBase3,
+    RelatedModel,
+    RelationModel,
 )
 
 
@@ -193,3 +196,19 @@ class ManagersRegressionTests(TestCase):
             del settings.TEST_SWAPPABLE_MODEL
             cache.app_models = old_app_models
             cache.app_store = old_app_store
+
+    def test_regress_3871(self):
+        related = RelatedModel.objects.create()
+
+        relation = RelationModel()
+        relation.fk = related
+        relation.gfk = related
+        relation.save()
+        relation.m2m.add(related)
+
+        t = Template('{{ related.test_fk.all.0 }}{{ related.test_gfk.all.0 }}{{ related.test_m2m.all.0 }}')
+
+        self.assertEqual(
+            t.render(Context({'related': related})),
+            ''.join([force_text(relation.pk)] * 3),
+        )