NPE: some validation errors don't provide a query path
Some validation errors don't provide a query path, e.g. `LoneAnonymousOperation`. This results in a NPE in the call to `toJsonArray` in line 75 of the `ExecutionErrorsService`.

Would it be better to provide an empty path or null?
diff --git a/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExecutionErrorsService.java b/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExecutionErrorsService.java
index a0df1b7f..372a08cf 100644
--- a/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExecutionErrorsService.java
+++ b/server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExecutionErrorsService.java
@@ -117,9 +117,11 @@ public class ExecutionErrorsService {
 
     private JsonArray toJsonArray(List<?> list) {
         JsonArrayBuilder arrayBuilder = jsonBuilderFactory.createArrayBuilder();
-        for (Object o : list) {
-            if (o != null)
-                arrayBuilder.add(o.toString());
+        if (list != null && !list.isEmpty()) {
+            for (Object o : list) {
+                if (o != null)
+                    arrayBuilder.add(o.toString());
+            }
         }
         return arrayBuilder.build();
     }
['server/implementation/src/main/java/io/smallrye/graphql/execution/error/ExecutionErrorsService.java']