Fix #8077

rest_framework/exceptions.py

@@ -142,7 +142,7 @@ class ValidationError(APIException):
     default_detail = _('Invalid input.')
     default_code = 'invalid'
 
-    def __init__(self, detail=None, code=None):
+    def __init__(self, detail=None, code=None, params=None):
         if detail is None:
             detail = self.default_detail
         if code is None:
@@ -151,8 +151,17 @@ class ValidationError(APIException):
         # For validation failures, we may collect many errors together,
         # so the details should always be coerced to a list if not already.
         if isinstance(detail, tuple):
+            detail_list = list()
+            if params is not None:
+                for msg in detail:
+                    detail_list.append(msg % params)
+                detail = detail_list
+            else:
                 detail = list(detail)
         elif not isinstance(detail, dict) and not isinstance(detail, list):
+            if params is not None:
+                detail = [detail % params]
+            else:
                 detail = [detail]
 
         self.detail = _get_error_details(detail, code)

tests/test_validation_error.py

@@ -109,3 +109,16 @@ class TestValidationErrorConvertsTuplesToLists(TestCase):
         assert len(error.detail) == 2
         assert str(error.detail[0]) == 'message1'
         assert str(error.detail[1]) == 'message2'
+
+class TestvalidationErrorWithDjangoStyle(TestCase):
+    def test_validation_error_details(self):
+        error = ValidationError('Invalid value: %(value)s', params={'value': '42'})
+        s = str(error.detail)
+        assert str(error.detail[0]) == 'Invalid value: 42'
+    
+    def test_validation_error_details_tuple(self):
+        error = ValidationError(detail=('Invalid value: %(value1)s', 'Invalid value: %(value2)s'), params={'value1': '42', 'value2':'43'})
+        assert isinstance(error.detail, list)
+        assert len(error.detail) == 2
+        assert str(error.detail[0]) == 'Invalid value: 42'
+        assert str(error.detail[1]) == 'Invalid value: 43'