Merge 513f8525db into fc70c0862f

rest_framework/settings.py

@@ -18,6 +18,8 @@ REST framework settings, checking for user settings first, then falling
 back to the defaults.
 """
 from __future__ import unicode_literals
+from collections import Iterable
+from django.core.exceptions import ImproperlyConfigured
 from django.conf import settings
 from django.utils import importlib, six
 from rest_framework import ISO_8601
@@ -187,6 +189,29 @@ class APISettings(object):
         except KeyError:
             # Fall back to defaults
             val = self.defaults[attr]
+        else:
+            # Verify that the user hasn't accidentally given a string instead
+            #  of an iterable, or vice-versa
+            default = self.defaults[attr]
+            if issubclass(val.__class__, Iterable) \
+                    and (not issubclass(default.__class__, Iterable)
+                         or isinstance(val, six.string_types)):
+                raise ImproperlyConfigured(
+                    'The "{settings_key}" setting must be a list or tuple, but '
+                    'got type "{type_name}" with value "{value}".'.format(
+                        settings_key=attr, type_name=val.__class__.__name__,
+                        value=val
+                    )
+                )
+            elif isinstance(default, six.string_types) and not \
+                    isinstance(val, six.string_types):
+                raise ImproperlyConfigured(
+                    'The "{settings_key}" setting must be a string, but '
+                    'got type "{type_name}" with value "{value}".'.format(
+                        settings_key=attr, type_name=val.__class__.__name__,
+                        value=val
+                    )
+                )
 
         # Coerce import strings into classes
         if val and attr in self.import_strings:

tests/test_settings.py

@@ -1,5 +1,8 @@
 from __future__ import unicode_literals
+from django.core.exceptions import ImproperlyConfigured
+import pytest
 from django.test import TestCase
+from django.utils import six
 from rest_framework.settings import APISettings
 
 
@@ -15,3 +18,46 @@ class TestSettings(TestCase):
         })
         with self.assertRaises(ImportError):
             settings.DEFAULT_RENDERER_CLASSES
+
+    def test_bad_iterable_setting_class_raises_warning(self):
+        """
+        Make sure errors are raised when settings which should be iterable are
+        not.
+        """
+        settings = APISettings({
+            'DEFAULT_RENDERER_CLASSES': 'rest_framework.renderers.JSONRenderer'
+        })
+
+        # Trigger the exception
+        with pytest.raises(ImproperlyConfigured) as exc_info:
+            settings.DEFAULT_RENDERER_CLASSES
+
+        # Construct the expected error message
+        text_type_name = str(six.text_type.__name__)
+        expected_error = (
+            'The "DEFAULT_RENDERER_CLASSES" setting must be a list or '
+            'tuple, but got type "{text_type_name}" with value '
+            '"rest_framework.renderers.JSONRenderer".'.format(
+                text_type_name=text_type_name
+            )
+        )
+        assert exc_info.value.args[0] == expected_error
+
+    def test_bad_string_setting_class_raises_warning(self):
+        """
+        Make sure errors are raised when settings which should be strings are
+        not.
+        """
+        settings = APISettings({
+            'DEFAULT_METADATA_CLASS': []
+        })
+
+        # Trigger the exception
+        with pytest.raises(ImproperlyConfigured) as exc_info:
+            settings.DEFAULT_METADATA_CLASS
+
+        expected_error = (
+            'The "DEFAULT_METADATA_CLASS" setting must be a string, but got '
+            'type "list" with value "[]".'
+        )
+        assert exc_info.value.args[0] == expected_error