Description Andrey Skorikov 2011-07-27 06:53:16 EDT

The ETL engine does not check the parameter types of the extended rules in ETL.
I have two classes State and Event, which have a superclass Node.
Now I try to map them to the corresponding classes Place and Transition, which have a superclass Element. I consider the mapping of States to Places only.
I defined two ETL rules:

@abstract
rule Elements
transform src : Source!Node
to dest : Target!Element {
	dest.name := src.name;
}

rule States2Places
transform src : Source!State
to dest : Target!Place
extends Elements {
	dest.foo := src.bar;
}

However, if I change the types of the Elements rule following happens:

@abstract
rule Elements
transform src : Source!Event
to dest : Target!Element

In this case, since State is not a subtype of Event, the transformation
of states simply does not happen at all: the engine just skips the
execution of the States2Places rule. This is strange because the rule
definitions are inconsistent (the extension does not make sense).

Otherwise, if I change the rule to:

@abstract
rule lements
transform src : Source!Node
to dest : Target!Transition

the States2Places rule is executed without complaints, which is also strange,
because Place is not a subtype of Transition.

In both cases I would expect some kind of error raised, but in the
implementation it is not the case.