core: add log for send-mail-error

packages/hydrooj/src/service/bus.ts

@@ -1,6 +1,8 @@
 /* eslint-disable no-await-in-loop */
 import cluster from 'cluster';
-import { Db, FilterQuery, OnlyFieldsOfType } from 'mongodb';
+import type {
+    Db, FilterQuery, ObjectID, OnlyFieldsOfType,
+} from 'mongodb';
 import { argv } from 'yargs';
 import { Logger } from '../logger';
 import type {
@@ -57,6 +59,12 @@ export interface EventMap {
         $set: any, $unset: OnlyFieldsOfType<DocType[T], any, true | '' | 1>
     ) => VoidReturn
 
+    'discussion/before-add': (
+        domainId: string, parentType: number, parentId: ObjectID | number | string,
+        owner: number, title: string, content: string,
+        ip: string | null, highlight: boolean, pin: boolean
+    ) => VoidReturn
+
     'problem/before-edit': (doc: Partial<Pdoc>) => VoidReturn
     'problem/edit': (doc: Pdoc) => VoidReturn
     'problem/list': (query: FilterQuery<Pdoc>, handler: any) => VoidReturn