upload: Content-type is always defined.

zerver/lib/upload/__init__.py

@@ -119,7 +119,7 @@ def sanitize_name(value: str) -> str:
 def upload_message_attachment(
     uploaded_file_name: str,
     uploaded_file_size: int,
-    content_type: Optional[str],
+    content_type: str,
     file_data: bytes,
     user_profile: UserProfile,
     target_realm: Optional[Realm] = None,

zerver/lib/upload/base.py

@@ -38,7 +38,7 @@ class ZulipUploadBackend:
         self,
         path_id: str,
         uploaded_file_size: int,
-        content_type: Optional[str],
+        content_type: str,
         file_data: bytes,
         user_profile: UserProfile,
         target_realm: Realm,

zerver/lib/upload/local.py

@@ -81,7 +81,7 @@ class LocalUploadBackend(ZulipUploadBackend):
         self,
         path_id: str,
         uploaded_file_size: int,
-        content_type: Optional[str],
+        content_type: str,
         file_data: bytes,
         user_profile: UserProfile,
         target_realm: Realm,

zerver/lib/upload/s3.py

@@ -205,7 +205,7 @@ class S3UploadBackend(ZulipUploadBackend):
         self,
         path_id: str,
         uploaded_file_size: int,
-        content_type: Optional[str],
+        content_type: str,
         file_data: bytes,
         user_profile: UserProfile,
         target_realm: Realm,

zerver/tests/test_upload_s3.py

@@ -95,18 +95,6 @@ class S3Test(ZulipTestCase):
         # Ensure the correct realm id of the target realm is used instead of the bot's realm.
         self.assertTrue(url.startswith(f"/user_uploads/{zulip_realm.id}/"))
 
-    @use_s3_backend
-    def test_upload_message_attachment_s3_with_undefined_content_type(self) -> None:
-        bucket = create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)[0]
-
-        user_profile = self.example_user("hamlet")
-        url = upload_message_attachment("dummy.txt", len(b"zulip!"), None, b"zulip!", user_profile)
-
-        path_id = re.sub(r"/user_uploads/", "", url)
-        self.assertEqual(b"zulip!", bucket.Object(path_id).get()["Body"].read())
-        uploaded_file = Attachment.objects.get(owner=user_profile, path_id=path_id)
-        self.assert_length(b"zulip!", uploaded_file.size)
-
     @use_s3_backend
     def test_delete_message_attachment(self) -> None:
         bucket = create_s3_buckets(settings.S3_AUTH_UPLOADS_BUCKET)[0]