[rules-users] not sure if this is a bug of drools or my bad usage...

[Simon Chen]

Hi all,

An interesting finding:

I have three simple rules:
rule "A2B"
	when
		A()
	then
		insertLogical(new B());
end
rule "B2C"
	when
		B()
	then
		insertLogical(new C());
end
rule "C2B"
	when
		C()
	then
		insertLogical(new B());
end

Basically, once we have an A(), we'll logically insert a B(). Once we
have a B(), we'll logically insert a C(). Once we have a C(), we'll
logically insert a B().

So, I first insert an A(), print all the objects. Retract A(), and
print all the objects. Here's what I got:
com.sample.B at 42
com.sample.C at 43
com.sample.A at 548997d1
after retract!
com.sample.B at 42
com.sample.C at 43

So, B() and C(), which should be logically depend on A(), somehow are
not retracted. The problem I see is the truth maintenance system allow
B() and C() to depend on each other, thus not affected by losing A().

Is this a bug or my bad usage?

Thanks.
-Simon