Refactored ValidationError to allow persisting error params and error codes as the exception bubbles up

django/core/exceptions.py

@@ -3,6 +3,9 @@ Global Django exception and warning classes.
 """
 import logging
 from functools import reduce
+import operator
+
+from django.utils.encoding import force_text
 
 
 class DjangoRuntimeWarning(RuntimeWarning):
@@ -74,46 +77,67 @@ NON_FIELD_ERRORS = '__all__'
 class ValidationError(Exception):
     """An error while validating data."""
     def __init__(self, message, code=None, params=None):
-        import operator
-        from django.utils.encoding import force_text
         """
         ValidationError can be passed any object that can be printed (usually
         a string), a list of objects or a dictionary.
         """
         if isinstance(message, dict):
-            self.message_dict = message
-            # Reduce each list of messages into a single list.
-            message = reduce(operator.add, message.values())
-
-        if isinstance(message, list):
-            self.messages = [force_text(msg) for msg in message]
+            self.error_dict = message
+        elif isinstance(message, list):
+            self.error_list = message
         else:
             self.code = code
             self.params = params
-            message = force_text(message)
-            self.messages = [message]
+            self.message = message
+            self.error_list = [self]
+
+    @property
+    def message_dict(self):
+        message_dict = {}
+        for field, messages in self.error_dict.items():
+            message_dict[field] = []
+            for message in messages:
+                if isinstance(message, ValidationError):
+                    message_dict[field].extend(message.messages)
+                else:
+                    message_dict[field].append(force_text(message))
+        return message_dict
+
+    @property
+    def messages(self):
+        if hasattr(self, 'error_dict'):
+            message_list = reduce(operator.add, self.error_dict.values())
+        else:
+            message_list = self.error_list
+
+        messages = []
+        for message in message_list:
+            if isinstance(message, ValidationError):
+                params = message.params
+                message = message.message
+                if params:
+                    message %= params
+                message = force_text(message)
+            else:
+                message = force_text(message)
+            messages.append(message)
+        return messages
 
     def __str__(self):
-        # This is needed because, without a __str__(), printing an exception
-        # instance would result in this:
-        # AttributeError: ValidationError instance has no attribute 'args'
-        # See http://www.python.org/doc/current/tut/node10.html#handling
-        if hasattr(self, 'message_dict'):
+        if hasattr(self, 'error_dict'):
             return repr(self.message_dict)
         return repr(self.messages)
 
     def __repr__(self):
-        if hasattr(self, 'message_dict'):
-            return 'ValidationError(%s)' % repr(self.message_dict)
-        return 'ValidationError(%s)' % repr(self.messages)
+        return 'ValidationError(%s)' % self
 
     def update_error_dict(self, error_dict):
-        if hasattr(self, 'message_dict'):
+        if hasattr(self, 'error_dict'):
             if error_dict:
-                for k, v in self.message_dict.items():
+                for k, v in self.error_dict.items():
                     error_dict.setdefault(k, []).extend(v)
             else:
-                error_dict = self.message_dict
+                error_dict = self.error_dict
         else:
-            error_dict[NON_FIELD_ERRORS] = self.messages
+            error_dict[NON_FIELD_ERRORS] = self.error_list
         return error_dict

django/db/models/base.py

@@ -910,7 +910,7 @@ class Model(six.with_metaclass(ModelBase)):
                 'field_label': six.text_type(field_labels)
             }
 
-    def full_clean(self, exclude=None):
+    def full_clean(self, exclude=None, validate_unique=True):
         """
         Calls clean_fields, clean, and validate_unique, on the model,
         and raises a ``ValidationError`` for any errors that occurred.
@@ -932,13 +932,14 @@ class Model(six.with_metaclass(ModelBase)):
             errors = e.update_error_dict(errors)
 
         # Run unique checks, but only for fields that passed validation.
-        for name in errors.keys():
-            if name != NON_FIELD_ERRORS and name not in exclude:
-                exclude.append(name)
-        try:
-            self.validate_unique(exclude=exclude)
-        except ValidationError as e:
-            errors = e.update_error_dict(errors)
+        if validate_unique:
+            for name in errors.keys():
+                if name != NON_FIELD_ERRORS and name not in exclude:
+                    exclude.append(name)
+            try:
+                self.validate_unique(exclude=exclude)
+            except ValidationError as e:
+                errors = e.update_error_dict(errors)
 
         if errors:
             raise ValidationError(errors)
@@ -963,7 +964,7 @@ class Model(six.with_metaclass(ModelBase)):
             try:
                 setattr(self, f.attname, f.clean(raw_value, self))
             except ValidationError as e:
-                errors[f.name] = e.messages
+                errors[f.name] = e.error_list
 
         if errors:
             raise ValidationError(errors)

django/db/models/fields/__init__.py

@@ -208,12 +208,9 @@ class Field(object):
                 v(value)
             except exceptions.ValidationError as e:
                 if hasattr(e, 'code') and e.code in self.error_messages:
-                    message = self.error_messages[e.code]
-                    if e.params:
-                        message = message % e.params
-                    errors.append(message)
-                else:
-                    errors.extend(e.messages)
+                    e.message = self.error_messages[e.code]
+                errors.extend(e.error_list)
+
         if errors:
             raise exceptions.ValidationError(errors)
 

django/forms/fields.py

@@ -136,12 +136,8 @@ class Field(object):
                 v(value)
             except ValidationError as e:
                 if hasattr(e, 'code') and e.code in self.error_messages:
-                    message = self.error_messages[e.code]
-                    if e.params:
-                        message = message % e.params
-                    errors.append(message)
-                else:
-                    errors.extend(e.messages)
+                    e.message = self.error_messages[e.code]
+                errors.extend(e.error_list)
         if errors:
             raise ValidationError(errors)
 
@@ -974,7 +970,7 @@ class MultiValueField(Field):
                 # Collect all validation errors in a single list, which we'll
                 # raise at the end of clean(), rather than raising a single
                 # exception for the first error we encounter.
-                errors.extend(e.messages)
+                errors.extend(e.error_list)
         if errors:
             raise ValidationError(errors)
 

django/forms/models.py

@@ -389,17 +389,11 @@ class BaseModelForm(BaseForm):
             if isinstance(field, InlineForeignKeyField):
                 exclude.append(f_name)
 
-        # Clean the model instance's fields.
         try:
-            self.instance.clean_fields(exclude=exclude)
+            self.instance.full_clean(exclude=exclude,
+                validate_unique=False)
         except ValidationError as e:
-            self._update_errors(e.message_dict)
-
-        # Call the model instance's clean method.
-        try:
-            self.instance.clean()
-        except ValidationError as e:
-            self._update_errors({NON_FIELD_ERRORS: e.messages})
+            self._update_errors(e)
 
         # Validate uniqueness if needed.
         if self._validate_unique:
@@ -414,7 +408,7 @@ class BaseModelForm(BaseForm):
         try:
             self.instance.validate_unique(exclude=exclude)
         except ValidationError as e:
-            self._update_errors(e.message_dict)
+            self._update_errors(e)
 
     def save(self, commit=True):
         """

tests/validators/tests.py

@@ -213,7 +213,7 @@ class TestSimpleValidators(TestCase):
         self.assertEqual(repr(v), str_prefix("ValidationError([%(_)s'First Problem', %(_)s'Second Problem'])"))
 
     def test_message_dict(self):
-        v = ValidationError({'first': 'First Problem'})
+        v = ValidationError({'first': ['First Problem']})
         self.assertEqual(str(v), str_prefix("{%(_)s'first': %(_)s'First Problem'}"))
         self.assertEqual(repr(v), str_prefix("ValidationError({%(_)s'first': %(_)s'First Problem'})"))