Don't truncate files when asked to copy them onto themselves. (bug 767120)

apps/amo/storage_utils.py

@@ -46,6 +46,8 @@ def copy_stored_file(src_path, dest_path, storage=default_storage,
 
     Each path will be managed by the same storage implementation.
     """
+    if src_path == dest_path:
+        return
     with storage.open(src_path, 'rb') as src:
         with storage.open(dest_path, 'wb') as dest:
             done = False

apps/amo/tests/test_storage_utils.py

@@ -93,6 +93,12 @@ class TestFileOps(unittest.TestCase):
         copy_stored_file(src, dest)
         eq_(self.contents(dest), '<contents>')
 
+    def test_self_copy(self):
+        src = self.newfile('src.txt', '<contents>')
+        dest = self.path('src.txt')
+        copy_stored_file(src, dest)
+        eq_(self.contents(dest), '<contents>')
+
     def test_move(self):
         src = self.newfile('src.txt', '<contents>')
         dest = self.path('somedir/dest.txt')

apps/files/tests/test_models.py

@@ -140,7 +140,7 @@ class TestFile(amo.tests.TestCase, amo.tests.AMOPaths):
         assert hide_mock.called
 
     @mock.patch('files.models.File.unhide_disabled_file')
-    def test_unhide_disabled_file(self, unhide_mock):
+    def test_unhide_on_enable(self, unhide_mock):
         f = File.objects.get(pk=67442)
         f.status = amo.STATUS_PUBLIC
         f.save()
@@ -156,6 +156,15 @@ class TestFile(amo.tests.TestCase, amo.tests.AMOPaths):
         f.save()
         assert unhide_mock.called
 
+    def test_unhide_disabled_files(self):
+        f = File.objects.get(pk=67442)
+        f.status = amo.STATUS_PUBLIC
+        with storage.open(f.guarded_file_path, 'wb') as fp:
+            fp.write('some data\n')
+        f.unhide_disabled_file()
+        assert storage.exists(f.file_path)
+        assert storage.open(f.file_path).size
+
     def test_unhide_disabled_file_mirroring(self):
         tmp = tempfile.mkdtemp()
         self.addCleanup(lambda: shutil.rmtree(tmp))