fix tests

Signed-off-by: jorgee <jorge.ejarque@seqera.io>

Author: jorgee

modules/nextflow/src/main/groovy/nextflow/util/SerializationHelper.groovy

@@ -112,6 +112,10 @@ class KryoHelper {
         kryo.addDefaultSerializer(GString, GStringSerializer)
         // map entry serializer
         kryo.addDefaultSerializer(Map.Entry, MapEntrySerializer)
+        // register PathSerializer as default for all Path implementations not explicitly registered
+        // (e.g. JimfsPath used in tests) to prevent Kryo's FieldSerializer from recursing into
+        // internal fields that may contain non-serializable objects such as lambdas (Guava 33.4+)
+        kryo.addDefaultSerializer(Path, PathSerializer)
 
         return kryo
     }

modules/nf-commons/src/main/nextflow/plugin/HttpPluginRepository.groovy

@@ -152,7 +152,7 @@ class HttpPluginRepository implements PrefetchUpdateRepository {
         }
         try {
             final ListDependenciesResponse decoded = encoder.decode(body)
-            if( decoded.plugins == null ) {
+            if( !decoded.plugins ) {
                 throw new PluginRuntimeException("Failed to download plugin metadata: Failed to parse response body")
             }
             final result = new HashMap<String, PluginInfo>()