fix

prompt/api.py

@@ -8,6 +8,7 @@ from django.contrib.auth.decorators import login_required
 
 from django.db.models import Count, Prefetch
 from .models import Conversation, Message
+from .utils import get_preceding_user_message
 from .schemas import ConversationOut, MessageOut, PromptHistoryItemOut
 from account.models import RoleChoices
 
@@ -166,16 +167,15 @@ def delete_message_pair(request, message_id: int):
     if asst_msg.conversation.user != request.user and request.user.role != RoleChoices.SUPER:
         raise HttpError(403, "只能删除自己的消息")
 
+    if asst_msg.submission_id and request.user.role != RoleChoices.SUPER:
+        from submission.models import Rating, SubmissionAward
+        has_ratings = Rating.objects.filter(submission_id=asst_msg.submission_id).exists()
+        has_awards = SubmissionAward.objects.filter(submission_id=asst_msg.submission_id).exists()
+        if has_ratings or has_awards:
+            raise HttpError(400, "该消息关联的提交已被评分或获奖，无法删除")
+
     # Find the preceding user message
-    user_msg = (
-        Message.objects.filter(
-            conversation=asst_msg.conversation,
-            created__lt=asst_msg.created,
-            role="user",
-        )
-        .order_by("-created")
-        .first()
-    )
+    user_msg = get_preceding_user_message(asst_msg)
 
     # Delete messages first, then submission
     submission_id = asst_msg.submission_id  # capture before deletion nulls it
@@ -187,10 +187,7 @@ def delete_message_pair(request, message_id: int):
     submission_deleted = False
     if submission_id:
         from submission.models import Submission as SubmissionModel
-        try:
-            SubmissionModel.objects.filter(id=submission_id).delete()
-            submission_deleted = True
-        except Exception:
-            pass
+        SubmissionModel.objects.filter(id=submission_id).delete()
+        submission_deleted = True
 
     return {"deleted": True, "submission_deleted": submission_deleted}

prompt/consumers.py

@@ -1,8 +1,8 @@
 import json
 from channels.generic.websocket import AsyncWebsocketConsumer
 from channels.db import database_sync_to_async
-from django.db.models import Count
-from .models import Conversation, Message
+from .models import Message
+from .utils import get_or_create_active_conversation
 from .llm import stream_chat, extract_code, stream_guidance, parse_guidance_response
 
 
@@ -79,15 +79,7 @@ class PromptConsumer(AsyncWebsocketConsumer):
 
     @database_sync_to_async
     def get_or_create_conversation(self):
-        conv = (
-            Conversation.objects.filter(user=self.user, task_id=self.task_id)
-            .annotate(msg_count=Count("messages"))
-            .order_by("-msg_count", "-created")
-            .first()
-        )
-        if not conv:
-            conv = Conversation.objects.create(user=self.user, task_id=self.task_id)
-        return conv
+        return get_or_create_active_conversation(self.user, self.task_id)
 
     @database_sync_to_async
     def delete_message(self, message):
@@ -195,15 +187,7 @@ class GuidanceConsumer(AsyncWebsocketConsumer):
 
     @database_sync_to_async
     def get_or_create_conversation(self):
-        conv = (
-            Conversation.objects.filter(user=self.user, task_id=self.task_id)
-            .annotate(msg_count=Count("messages"))
-            .order_by("-msg_count", "-created")
-            .first()
-        )
-        if not conv:
-            conv = Conversation.objects.create(user=self.user, task_id=self.task_id)
-        return conv
+        return get_or_create_active_conversation(self.user, self.task_id)
 
     @database_sync_to_async
     def delete_message(self, message):

prompt/utils.py

@@ -0,0 +1,32 @@
+from django.db.models import Count, Q
+from .models import Conversation
+
+
+def get_active_conversation(user, task_id):
+    """Return the conversation with the most messages for this user+task, or None."""
+    return (
+        Conversation.objects.filter(user=user, task_id=task_id)
+        .annotate(msg_count=Count("messages"))
+        .order_by("-msg_count", "-created")
+        .first()
+    )
+
+
+def get_or_create_active_conversation(user, task_id):
+    conv = get_active_conversation(user, task_id)
+    if not conv:
+        conv = Conversation.objects.create(user=user, task_id=task_id)
+    return conv
+
+
+def get_preceding_user_message(asst_msg):
+    """Return the user message immediately preceding an assistant message in its conversation."""
+    return (
+        asst_msg.conversation.messages.filter(role="user")
+        .filter(
+            Q(created__lt=asst_msg.created)
+            | Q(created=asst_msg.created, id__lt=asst_msg.id)
+        )
+        .order_by("-created", "-id")
+        .first()
+    )