Ensure serializer and field validators support both lists and tuples

rest_framework/fields.py

@@ -350,7 +350,7 @@ def __init__(self, read_only=False, write_only=False,
                 self.default_empty_html = default
 
         if validators is not None:
-            self.validators = validators[:]
+            self.validators = list(validators)
 
         # These are set up by `.bind()` when the field is added to a serializer.
         self.field_name = None
@@ -410,7 +410,7 @@ def validators(self, validators):
         self._validators = validators
 
     def get_validators(self):
-        return self.default_validators[:]
+        return list(self.default_validators)
 
     def get_initial(self):
         """

rest_framework/serializers.py

@@ -393,7 +393,7 @@ def get_validators(self):
         # Used by the lazily-evaluated `validators` property.
         meta = getattr(self, 'Meta', None)
         validators = getattr(meta, 'validators', None)
-        return validators[:] if validators else []
+        return list(validators) if validators else []
 
     def get_initial(self):
         if hasattr(self, 'initial_data'):
@@ -1480,7 +1480,7 @@ def get_validators(self):
         # If the validators have been declared explicitly then use that.
         validators = getattr(getattr(self, 'Meta', None), 'validators', None)
         if validators is not None:
-            return validators[:]
+            return list(validators)
 
         # Otherwise use the default set of validators.
         return (

tests/test_fields.py

@@ -740,6 +740,25 @@ def test_null_bytes(self):
                 'Null characters are not allowed.'
             ]
 
+    def test_iterable_validators(self):
+        """
+        Ensure `validators` parameter is compatible with reasonable iterables.
+        """
+        value = 'example'
+
+        for validators in ([], (), set()):
+            field = serializers.CharField(validators=validators)
+            field.run_validation(value)
+
+        def raise_exception(value):
+            raise exceptions.ValidationError('Raised error')
+
+        for validators in ([raise_exception], (raise_exception,), set([raise_exception])):
+            field = serializers.CharField(validators=validators)
+            with pytest.raises(serializers.ValidationError) as exc_info:
+                field.run_validation(value)
+            assert exc_info.value.detail == ['Raised error']
+
 
 class TestEmailField(FieldValues):
     """

tests/test_serializer.py

@@ -10,7 +10,7 @@
 import pytest
 from django.db import models
 
-from rest_framework import fields, relations, serializers
+from rest_framework import exceptions, fields, relations, serializers
 from rest_framework.compat import unicode_repr
 from rest_framework.fields import Field
 
@@ -183,6 +183,38 @@ def to_internal_value(self, data):
         assert serializer.validated_data.coords[1] == 50.941357
         assert serializer.errors == {}
 
+    def test_iterable_validators(self):
+        """
+        Ensure `validators` parameter is compatible with reasonable iterables.
+        """
+        data = {'char': 'abc', 'integer': 123}
+
+        for validators in ([], (), set()):
+            class ExampleSerializer(serializers.Serializer):
+                char = serializers.CharField(validators=validators)
+                integer = serializers.IntegerField()
+
+            serializer = ExampleSerializer(data=data)
+            assert serializer.is_valid()
+            assert serializer.validated_data == data
+            assert serializer.errors == {}
+
+        def raise_exception(value):
+            raise exceptions.ValidationError('Raised error')
+
+        for validators in ([raise_exception], (raise_exception,), set([raise_exception])):
+            class ExampleSerializer(serializers.Serializer):
+                char = serializers.CharField(validators=validators)
+                integer = serializers.IntegerField()
+
+            serializer = ExampleSerializer(data=data)
+            assert not serializer.is_valid()
+            assert serializer.data == data
+            assert serializer.validated_data == {}
+            assert serializer.errors == {'char': [
+                exceptions.ErrorDetail(string='Raised error', code='invalid')
+            ]}
+
 
 class TestValidateMethod:
     def test_non_field_error_validate_method(self):