Fix engine hang with non-existent service ID (#1050)

CHANGELOG.md

@@ -2,7 +2,15 @@
 
 All changes that impact users of this module are documented in this file, in the [Common Changelog](https://common-changelog.org) format with some additional specifications defined in the CONTRIBUTING file. This codebase adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## Unreleased
+## Unreleased [patch]
+
+_Full changeset and discussions: [#1050](https://github.com/OpenTermsArchive/engine/pull/1050)._
+
+> Development of this release was supported by the [French Ministry for Foreign Affairs](https://www.diplomatie.gouv.fr/fr/politique-etrangere-de-la-france/diplomatie-numerique/) through its ministerial [State Startups incubator](https://beta.gouv.fr/startups/open-terms-archive.html) under the aegis of the Ambassador for Digital Affairs.
+
+### Fixed
+
+- Fix engine hang with non-existent service ID
 
 ## 0.34.2 - 2024-02-12
 

src/archivist/index.js

@@ -112,7 +112,9 @@ export default class Archivist extends events.EventEmitter {
       });
     });
 
-    await this.trackingQueue.drain();
+    if (this.trackingQueue.length()) {
+      await this.trackingQueue.drain();
+    }
 
     await Promise.all([ stopHeadlessBrowser(), this.recorder.finalize() ]);
     this.emit('trackingCompleted', servicesIds.length, Service.getNumberOfTerms(this.services, servicesIds), extractOnly);