Disable notification discussion fallback

src/notifications.py

@@ -6,9 +6,8 @@ leaderboard Space, which triggers Hugging Face's native notification.
 Configuration (see :mod:`src.envs`):
     * ``HF_TOKEN`` — token used to post the comment / discussion.
     * ``REPO_ID`` — the Space repo id (default notification target).
-    * ``NOTIFICATION_DISCUSSION_NUM`` — if set, comments are posted on this
-      existing discussion; if unset, a new discussion is created per
-      notification.
+        * ``NOTIFICATION_DISCUSSION_NUM`` — comments are posted on this existing
+            discussion. If unset, notification sending is skipped.
 """
 
 import logging
@@ -46,28 +45,25 @@ def send_hf_notification(
     repo_id = repo_id or REPO_ID
     if discussion_num is None:
         discussion_num = NOTIFICATION_DISCUSSION_NUM
+    if not discussion_num:
+        logger.warning(
+            "[notify] NOTIFICATION_DISCUSSION_NUM not set — skipping notification for %r",
+            username,
+        )
+        return None
 
     now = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S UTC")
     comment = f"@{username}\n\n{message}\n\nTime: {now}"
 
     api = HfApi(token=HF_TOKEN)
     try:
-        if discussion_num:
-            api.comment_discussion(
-                repo_id=repo_id,
-                repo_type="space",
-                discussion_num=int(discussion_num),
-                comment=comment,
-            )
-            url = f"https://huggingface.co/spaces/{repo_id}/discussions/{discussion_num}"
-        else:
-            discussion = api.create_discussion(
-                repo_id=repo_id,
-                repo_type="space",
-                title=f"Task notification for @{username}",
-                description=comment,
-            )
-            url = getattr(discussion, "url", f"https://huggingface.co/spaces/{repo_id}/discussions")
+        api.comment_discussion(
+            repo_id=repo_id,
+            repo_type="space",
+            discussion_num=int(discussion_num),
+            comment=comment,
+        )
+        url = f"https://huggingface.co/spaces/{repo_id}/discussions/{discussion_num}"
     except Exception:
         logger.error("[notify] failed to notify @%s", username, exc_info=True)
         return None