Remove delete() call from CompressorFileStorage.get_available_name (#1107)

* Remove delete() call from CompressorFileStorage.get_available_name

* Add a testcase for duplicate handling in save()

2 files changed, 16 insertions, 7 deletions

diff --git a/compressor/storage.py b/compressor/storage.py
index a9d7a0c..5d12eb8 100644
--- a/compressor/storage.py
+++ b/compressor/storage.py
@@ -33,13 +33,16 @@ class CompressorFileStorage(FileSystemStorage):
     def modified_time(self, name):
         return datetime.fromtimestamp(os.path.getmtime(self.path(name)))
 
-    def get_available_name(self, name, max_length=None):
-        """
-        Deletes the given file if it exists.
-        """
-        if self.exists(name):
-            self.delete(name)
-        return name
+    def save(self, filename, content):
+        temp_filename = super().save(filename, content)
+        # If a file already exists  in the target location, FileSystemStorage
+        # will generate an unique filename and save content there instead.
+        # When that happens, we move the file to the intended location using
+        # os.replace() (which is an atomic operation):
+        if temp_filename != filename:
+            os.replace(self.path(temp_filename), self.path(filename))
+
+        return filename
 
 
 compressor_file_storage = SimpleLazyObject(
diff --git a/compressor/tests/test_storages.py b/compressor/tests/test_storages.py
index 8a99e45..9168510 100644
--- a/compressor/tests/test_storages.py
+++ b/compressor/tests/test_storages.py
@@ -61,3 +61,9 @@ class StorageTestCase(TestCase):
         context = {'STATIC_URL': settings.COMPRESS_URL}
         out = css_tag("/static/CACHE/css/output.e701f86c6430.css")
         self.assertEqual(out, render(template, context))
+
+    def test_duplicate_save_overwrites_same_file(self):
+        filename1 = self.default_storage.save('test.txt', ContentFile('yeah yeah'))
+        filename2 = self.default_storage.save('test.txt', ContentFile('yeah yeah'))
+        self.assertEqual(filename1, filename2)
+        self.assertNotIn("_", filename2)