Invalidate event cache on duplicate key error

When a DB duplicate key error indicates the event already exists, clear any cached null result so a subsequent fetch retrieves the newly created document. This change computes the event cache key via getEventCacheKey(projectId, uniqueEventHash) and deletes it (this.cache.del) before retrying handle(task), preventing stale null caches from causing missed event repetitions.

Author: neSpecc

workers/grouper/src/index.ts

@@ -226,6 +226,14 @@ export default class GrouperWorker extends Worker {
          * and we need to process this event as repetition
          */
         if (e.code?.toString() === DB_DUPLICATE_KEY_ERROR) {
+          /**
+           * Invalidate cached null from getEvent so the retry
+           * fetches the now-existing document from the database
+           */
+          const eventCacheKey = await this.getEventCacheKey(task.projectId, uniqueEventHash);
+
+          this.cache.del(eventCacheKey);
+
           await this.handle(task);
 
           return;