Ticket #13584: allow_empty_file_formfield.diff

django/forms/fields.py

@@ -439 +439 @@
 
     def __init__(self, *args, **kwargs):
         self.max_length = kwargs.pop('max_length', None)
+        self.allow_empty_file = kwargs.pop('allow_empty_file', False)
         super(FileField, self).__init__(*args, **kwargs)
 
     def to_python(self, data):
@@ -457 +458 @@
             raise ValidationError(self.error_messages['max_length'] % error_values)
         if not file_name:
             raise ValidationError(self.error_messages['invalid'])
-        if not file_size:
+        if not self.allow_empty_file and not file_size:
             raise ValidationError(self.error_messages['empty'])
 
         return data

tests/regressiontests/forms/fields.py

@@ -463 +463 @@
         self.assertEqual('files/test2.pdf', f.clean(None, 'files/test2.pdf'))
         self.assertEqual(SimpleUploadedFile, type(f.clean(SimpleUploadedFile('name', 'Some File Content'))))
 
+    def test_filefield_ticket13584(self):
+        f = FileField(allow_empty_file = True)
+        self.assertEqual(SimpleUploadedFile, type(f.clean(SimpleUploadedFile('name', ''))))
+
     # URLField ##################################################################
 
     def test_urlfield_37(self):

docs/ref/forms/fields.txt

@@ -513 +513 @@
     * Empty value: ``None``
     * Normalizes to: An ``UploadedFile`` object that wraps the file content
       and file name into a single object.
-    * Validates that non-empty file data has been bound to the form.
+    * Can validate that non-empty file data has been bound to the form.
     * Error message keys: ``required``, ``invalid``, ``missing``, ``empty``
 
+Has one optional argument for validation, ``allow_empty_file``. If provided,
+validation will succeed even if the file content is empty.
+
 To learn more about the ``UploadedFile`` object, see the :ref:`file uploads
 documentation <topics-http-file-uploads>`.