Ticket #18233: fix_18233.diff

AUTHORS

@@ -563 +563 @@
     Gasper Zejn <zejn@kiberpipa.org>
     Jarek Zgoda <jarek.zgoda@gmail.com>
     Cheng Zhang
+    Aviral Dasgupta <aviraldg@gmail.com>
 
 A big THANK YOU goes to:
 

django/core/files/move.py

@@ -51 +51 @@
         return
 
     try:
+        if not allow_overwrite and os.path.exists(new_file_name):
+            raise IOError('Destination file already exists: \'{0}\''.format(new_file_name))
         os.rename(old_file_name, new_file_name)
         return
     except OSError:

tests/regressiontests/file_storage/tests.py

@@ -23 +23 @@
 from django.core.files.images import get_image_dimensions
 from django.core.files.storage import FileSystemStorage, get_storage_class
 from django.core.files.uploadedfile import UploadedFile
+from django.core.files.move import file_move_safe
 from django.test import SimpleTestCase
 from django.utils import unittest
 from ..servers.tests import LiveServerBase
@@ -586 +587 @@
         remote_file = self.urlopen('/example_view/')
 
         self.assertEqual(stored_file.read(), remote_file.read())
+
+class MoveTestCase(unittest.TestCase):
+    """
+    Test django.core.files.move.
+    """
+    def setUp(self):
+        self.file_a = tempfile.mkstemp()
+        self.file_b = tempfile.mkstemp()
+
+    def tearDown(self):
+        os.close(self.file_a[0])
+        os.close(self.file_b[0])
+        os.remove(self.file_a[1])
+        os.remove(self.file_b[1])
+
+    def test_overwrite_existing_file(self):
+        """
+        Test that file_move_safe raises an IOError if you try to overwrite an
+        existing file without passing in allow_overwrite=True.
+        """
+        self.assertRaises(IOError, file_move_safe, self.file_a[1], self.file_b[1])