From c5d6ecc84c5a40f5410bfd89b5a80c4e5a549d25 Mon Sep 17 00:00:00 2001
From: Zoltan Szalai <flack@pionlab.com>
Date: Sat, 25 Apr 2015 16:33:44 +0200
Subject: [PATCH 1/2] pass instance to view.get_serializer in metadata's
 determine_actions method since choices (especially querysets of related
 fields) can often depend on the instance

---
 rest_framework/metadata.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/rest_framework/metadata.py b/rest_framework/metadata.py
index b2c48b816..afef00fe6 100644
--- a/rest_framework/metadata.py
+++ b/rest_framework/metadata.py
@@ -74,19 +74,23 @@ class SimpleMetadata(BaseMetadata):
         actions = {}
         for method in set(['PUT', 'POST']) & set(view.allowed_methods):
             view.request = clone_request(request, method)
+            instance = None
             try:
                 # Test global permissions
                 if hasattr(view, 'check_permissions'):
                     view.check_permissions(view.request)
                 # Test object permissions
                 if method == 'PUT' and hasattr(view, 'get_object'):
-                    view.get_object()
+                    instance = view.get_object()
             except (exceptions.APIException, PermissionDenied, Http404):
                 pass
             else:
                 # If user has appropriate permissions for the view, include
                 # appropriate metadata about the fields that should be supplied.
-                serializer = view.get_serializer()
+                kwargs = {}
+                if instance is not None:
+                    kwargs['instance'] = instance
+                serializer = view.get_serializer(**kwargs)
                 actions[method] = self.get_serializer_info(serializer)
             finally:
                 view.request = request

From e52df6b5492aed16614fb9b8b5c3c85a0cd5c4c9 Mon Sep 17 00:00:00 2001
From: Zoltan Szalai <flack@pionlab.com>
Date: Sat, 25 Apr 2015 16:56:02 +0200
Subject: [PATCH 2/2] add TestMetadata.test_instance_passed_to_serializer

---
 tests/test_metadata.py | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/tests/test_metadata.py b/tests/test_metadata.py
index 731aedba3..747ef817d 100644
--- a/tests/test_metadata.py
+++ b/tests/test_metadata.py
@@ -212,3 +212,27 @@ class TestMetadata:
         options = metadata.SimpleMetadata()
         field_info = options.get_field_info(serializers.NullBooleanField())
         assert field_info['type'] == 'boolean'
+
+    def test_instance_passed_to_serializer(self):
+        dummy_obj = object()
+
+        class ExampleSerializer(serializers.Serializer):
+            def __init__(self, *args, **kwargs):
+                super(ExampleSerializer, self).__init__(*args, **kwargs)
+                assert self.instance == dummy_obj
+
+        class ExampleView(views.APIView):
+            """Example view."""
+            def put(self, request):
+                pass
+
+            def get_object(self):
+                return dummy_obj
+
+            def get_serializer(self, *args, **kwargs):
+                assert kwargs['instance'] == self.get_object()
+                return ExampleSerializer(*args, **kwargs)
+
+        view = ExampleView.as_view()
+        response = view(request=request)
+        assert response.status_code == status.HTTP_200_OK