Drools - Values in result of `from` caluse: are they facts? why Drools try to marshal them?

[Reza Same'ei]

I'm implementing a software using Drools and Saxon; In the LHS I use load a xml-dom (via `from` clause) 

and run some queries on it (using XPath); then I use that xml-dom in in RHS to generate a fact!

```

global XmlService xml;

rule "look for oid"

when

uri : String()

doc : Doc(

hasValue("/Tag/@OID")

) from xml.load(uri)

then

insert(new Id(doc.getValue("/Tag/@OID")));

end

```

When I insert a `String` (as `uri`) I see this line in logs:

```

15:55:57.540 INFO  org.drools.core.event.DebugAgendaEventListener - ==>[BeforeActivationFiredEvent:  getActivation()=[[ ... ] [ [fact 0:39:1623992162:1623992162:39:DEFAULT:NON_TRAIT:com.example.Doc:com.example.Doc@60cc2762]

```

Also when I'm trying to marshalize my session I see that Drools is trying to serialize them and because it's not `Serializable`, it fails.

I'll add this fact that when I try to retrieve facts from `KieSession` it don't return those values, it only returns `Id`s. but Drools also

prevent GC from removing those values from heap!

Is this behaviour normal? Is my understanding correct? How I can change it?

Drools/Kie version : 7.24.Final