Check for redundant on SerializerMethodField

1 files changed, 22 insertions, 7 deletions

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 446732c3..328e93ef 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -178,7 +178,7 @@ class Field(object):
         # In order to enforce a consistent style, we error if a redundant
         # 'source' argument has been used. For example:
         # my_field = serializer.CharField(source='my_field')
-        assert self._kwargs.get('source') != field_name, (
+        assert self.source != field_name, (
             "It is redundant to specify `source='%s'` on field '%s' in "
             "serializer '%s', because it is the same as the field name. "
             "Remove the `source` keyword argument." %
@@ -883,17 +883,32 @@ class SerializerMethodField(Field):
         def get_extra_info(self, obj):
             return ...  # Calculate some data to return.
     """
-    def __init__(self, method_attr=None, **kwargs):
-        self.method_attr = method_attr
+    def __init__(self, method_name=None, **kwargs):
+        self.method_name = method_name
         kwargs['source'] = '*'
         kwargs['read_only'] = True
         super(SerializerMethodField, self).__init__(**kwargs)
 
+    def bind(self, field_name, parent):
+        # In order to enforce a consistent style, we error if a redundant
+        # 'method_name' argument has been used. For example:
+        # my_field = serializer.CharField(source='my_field')
+        default_method_name = 'get_{field_name}'.format(field_name=field_name)
+        assert self.method_name != default_method_name, (
+            "It is redundant to specify `%s` on SerializerMethodField '%s' in "
+            "serializer '%s', because it is the same as the default method name. "
+            "Remove the `method_name` argument." %
+            (self.method_name, field_name, parent.__class__.__name__)
+        )
+
+        # The method name should default to `get_{field_name}`.
+        if self.method_name is None:
+            self.method_name = default_method_name
+
+        super(SerializerMethodField, self).bind(field_name, parent)
+
     def to_representation(self, value):
-        method_attr = self.method_attr
-        if method_attr is None:
-            method_attr = 'get_{field_name}'.format(field_name=self.field_name)
-        method = getattr(self.parent, method_attr)
+        method = getattr(self.parent, self.method_name)
         return method(value)