core: discussion_raw: add existance check

packages/hydrooj/src/handler/discussion.ts

@@ -363,7 +363,12 @@ class DiscussionRawHandler extends DiscussionHandler {
             this.response.body.history = await discussion.getHistory(domainId, drrid || drid || did);
         } else {
             const [doc] = await discussion.getHistory(domainId, drrid || drid || did, ts ? { time: new Date(ts) } : {});
-            if (!doc && ts) throw new DiscussionNotFoundError(drrid || drid || did);
+            if (!doc) {
+                if (ts) throw new DiscussionNotFoundError(drrid || drid || did);
+                if (drrid && !this.drrdoc) throw new DiscussionNotFoundError(drrid);
+                if (drid && !this.drdoc) throw new DiscussionNotFoundError(drid);
+                if (did && !this.ddoc) throw new DiscussionNotFoundError(did);
+            }
             this.response.type = 'text/markdown';
             this.response.body = doc ? doc.content : drrid ? this.drrdoc.content : drid ? this.drdoc.content : this.ddoc.content;
         }