From 1ece516d2d0d942d9de513f85d601afcccf67ebd Mon Sep 17 00:00:00 2001
From: Si Feng <si@feng.si>
Date: Tue, 19 Feb 2019 07:38:20 -0800
Subject: [PATCH] Adjusted field `validators` to accept iterables. (#6282)

Closes 6280.
---
 rest_framework/fields.py      |  4 ++--
 rest_framework/serializers.py |  4 ++--
 tests/test_fields.py          | 19 +++++++++++++++++++
 tests/test_serializer.py      | 34 +++++++++++++++++++++++++++++++++-
 4 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index 562e52b22..2cbfd22bb 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -350,7 +350,7 @@ class Field(object):
                 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 @@ class Field(object):
         self._validators = validators
 
     def get_validators(self):
-        return self.default_validators[:]
+        return list(self.default_validators)
 
     def get_initial(self):
         """
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py
index eae08a34c..9830edb3f 100644
--- a/rest_framework/serializers.py
+++ b/rest_framework/serializers.py
@@ -393,7 +393,7 @@ class Serializer(BaseSerializer):
         # 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 @@ class ModelSerializer(Serializer):
         # 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 (
diff --git a/tests/test_fields.py b/tests/test_fields.py
index 9a1d04979..12c936b22 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -740,6 +740,25 @@ class TestCharField(FieldValues):
                 '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):
     """
diff --git a/tests/test_serializer.py b/tests/test_serializer.py
index efa1adf0e..6e4ff22b2 100644
--- a/tests/test_serializer.py
+++ b/tests/test_serializer.py
@@ -10,7 +10,7 @@ from collections import Mapping
 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 @@ class TestSerializer:
         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):