extensions/models.py

@@ -683,6 +683,11 @@ class Version(CreatedModifiedMixin, TrackChangesMixin, models.Model):
 
     def add_file(self, file: File):
         current_platforms = set([p.slug for p in self.platforms.all()])
+        if not current_platforms:
+            raise ValueError(
+                f'add_file failed: Version pk={self.pk} is not platform-specific, '
+                f'no more files allowed'
+            )
         file_platforms = set(file.get_platforms() or [])
         if overlap := current_platforms & file_platforms:
             raise ValueError(

extensions/tests/test_models.py

@@ -131,6 +131,11 @@ class VersionTest(TestCase):
         with self.assertRaises(ValueError):
             version.add_file(file)
 
+        all_platforms_version = create_version(metadata__platforms=[])
+        file = FileFactory(metadata__platforms=['linux-x64'])
+        with self.assertRaises(ValueError):
+            all_platforms_version.add_file(file)
+
     def test_get_file_for_platform(self):
         version = create_version(metadata__platforms=['linux-x64'])
         file = FileFactory(metadata__platforms=['windows-x64'])