Merge pull request #18156 from overleaf/em-fix-queue-size-metric

Fix queue size by error metric in project history dashboard

GitOrigin-RevId: e837c6fc00acd23671f017c70cd9b2c643c02482

services/project-history/app/js/UpdatesProcessor.js

@@ -170,10 +170,11 @@ _mocks._countAndProcessUpdates = (
           _processUpdatesBatch(projectId, updates, extendLock, cb)
         },
         error => {
-          if (error) {
-            return callback(error)
-          }
-          callback(null, queueSize)
+          // Unconventional callback signature. The caller needs the queue size
+          // even when an error is thrown in order to record the queue size in
+          // the projectHistoryFailures collection. We'll have to find another
+          // way to achieve this when we promisify.
+          callback(error, queueSize)
         }
       )
     } else {