From 8af366a73282359c63eab6e81b80fb859604424f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jose=CC=81=20Padilla?= <jpadilla@webapplicate.com>
Date: Wed, 19 Aug 2015 11:38:31 -0400
Subject: [PATCH] Raise error when `source=` use on a child.

Closes #3292
---
 rest_framework/fields.py | 12 ++++++++++++
 tests/test_fields.py     | 18 ++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 67b1582c9..e2081abd4 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -1381,7 +1381,13 @@ class ListField(Field):
     def __init__(self, *args, **kwargs):
         self.child = kwargs.pop('child', copy.deepcopy(self.child))
         self.allow_empty = kwargs.pop('allow_empty', True)
+
         assert not inspect.isclass(self.child), '`child` has not been instantiated.'
+        assert self.child.source is None, (
+            "The `source` argument is not meaningful when applied to a `child=` field. "
+            "Remove `source=` from the field declaration."
+        )
+
         super(ListField, self).__init__(*args, **kwargs)
         self.child.bind(field_name='', parent=self)
 
@@ -1424,7 +1430,13 @@ class DictField(Field):
 
     def __init__(self, *args, **kwargs):
         self.child = kwargs.pop('child', copy.deepcopy(self.child))
+
         assert not inspect.isclass(self.child), '`child` has not been instantiated.'
+        assert self.child.source is None, (
+            "The `source` argument is not meaningful when applied to a `child=` field. "
+            "Remove `source=` from the field declaration."
+        )
+
         super(DictField, self).__init__(*args, **kwargs)
         self.child.bind(field_name='', parent=self)
 
diff --git a/tests/test_fields.py b/tests/test_fields.py
index 0fea45a33..58c1c9243 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -1416,6 +1416,15 @@ class TestListField(FieldValues):
     ]
     field = serializers.ListField(child=serializers.IntegerField())
 
+    def test_no_source_on_child(self):
+        with pytest.raises(AssertionError) as exc_info:
+            serializers.ListField(child=serializers.IntegerField(source='other'))
+
+        assert str(exc_info.value) == (
+            "The `source` argument is not meaningful when applied to a `child=` field. "
+            "Remove `source=` from the field declaration."
+        )
+
 
 class TestEmptyListField(FieldValues):
     """
@@ -1461,6 +1470,15 @@ class TestDictField(FieldValues):
     ]
     field = serializers.DictField(child=serializers.CharField())
 
+    def test_no_source_on_child(self):
+        with pytest.raises(AssertionError) as exc_info:
+            serializers.DictField(child=serializers.CharField(source='other'))
+
+        assert str(exc_info.value) == (
+            "The `source` argument is not meaningful when applied to a `child=` field. "
+            "Remove `source=` from the field declaration."
+        )
+
 
 class TestUnvalidatedDictField(FieldValues):
     """