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Issue with cached Helpers [message #1860621]

Tue, 22 August 2023 08:01

Yves BERNARD

Messages: 146
Registered: July 2014

Senior Member

I have defined a helper that has UML!Element as a context, no input parameter and that return a Boolean value.

It works fine with any input element kind except Association Classes. In that case, the following exception is raised:

org.eclipse.m2m.atl.emftvm.util.VMException: org.eclipse.m2m.atl.emftvm.util.DuplicateEntryException:

Superkeys
org.eclipse.emf.ecore.impl.EClassImpl@5f18a74d (name: Class) (instanceClassName: null) (abstract: false, interface: false) and
org.eclipse.emf.ecore.impl.EClassImpl@5b0d50a7 (name: Association) (instanceClassName: null) (abstract: false, interface: false)

both have an entry in
{...(map content)...}

If I rewrite the helper so that it has no context and take the element to be evaluated has an input parameter, it works fine with any kind of element, Association Classes as well.

So it looks like the problem comes from the map that the first version of the helper uses for caching its results and that does not work well with Association Classes.

Did you ever experience a similar issue and if so, did you find a workaround?

Thanks.

Yves

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Re: Issue with cached Helpers [message #1860637 is a reply to message #1860621]

Tue, 22 August 2023 18:07

Dennis Wagelaar

Messages: 581
Registered: September 2012
Location: Belgium

Senior Member

That's a bug allright. It's triggered by the multiple inheritance situation for AssociationClass. If you first invoke the helper attribute on a Class as well as an Association, EMFTVM will cache that helper attribute directly under Class and Association, so it won't have to traverse the inheritance hierarchy the next time you need to use the helper attribute on the same context type. See https://git.eclipse.org/c/mmt/org.eclipse.atl.git/tree/plugins/org.eclipse.m2m.atl.emftvm/src/org/eclipse/m2m/atl/emftvm/util/FieldContainer.java#n95

However, the code linked above is naive, and makes it look like the helper attribute in question is actually defined on both Class and Association, and a diamond problem exists when trying to use the helper attribute on the common subclass AssociationClass.

Cheers,
Dennis

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