[news.eclipse.technology.emft] Re: [EMF Compare] MergeService doesn't co

[Bryan Hunt <bhunt@xxxxxxx>]

Laurent,

Do you have an example on how we would implement the extension point?  
I looked at the extension point and didn't get very far.  Some 
documentation / examples would be helpful.

Bryan

On 2009-08-03 03:59:38 -0500, laurent Goubet <laurent.goubet@xxxxxxx> said:

> Hi Stephen,
>
> With two differences as you've described, EMF Compare will indeed need
> two steps for this child reference to be copied : you have an added
> element A with a reference towards the child C of another added element
> B. Merging only A will not copy C since B hasn't been copied yet, but
> merging B subsequently will copy C _and_ restore the link from A to C.
>
> We've implemented the merge as such so has to only merge the differences
> the user selected, not ones that are not directly linked. MergeService
> is final as it simply isn't meant to be subclassed, but you can force
> EMF Compare to consider your two differences to be linked (and thus
> needing to be merged together) through the use of the
> org.eclipse.emf.compare.diff.extension extension point.
>
> Laurent Goubet
> Obeo
>
> Stephen McCants a écrit :
> > Resending with proper subject line.
> > --Stephen
> >
> > -------- Original Message --------
> > Subject: MergeService doesn't copy a child non-containment reference
> > Date: Thu, 30 Jul 2009 13:39:39 -0500
> > From: Stephen McCants <stephenmccants@xxxxxxxxx>
> > Organization: EclipseCorner
> > Newsgroups: eclipse.technology.emft
> >
> > Hello,
> >
> > We have a model and are doing the match, diff and merge.  Everything is
> > working correctly, except
> > the merge fails to merge in one object.
> >
> > The diff correctly identifies an object that has been added to the
> > model.  That added object has a
> > non-containment reference to another object.  When we do the merge, it
> > correctly copies the added
> > object to the left model (from the right model), but the non-containment
> > reference is never set.
> > Instead of being set, it is null.
> >
> > We traced through the copy code and it is trying to copy it in
> > EMFComapreEObjectCopier.copyReferences() by calling copyReference().
> > However, the call to
> > copyReference() does nothing because we haven't copied it before (so it
> > isn't returned by get()) and
> > the mergeLinkedDiff() function returns false.
> >
> > The reason mergeLinkedDiff() returns false is because the reference
> > being copied is a child of an
> > unmatched element and not an unmatched element itself.
> >
> > We were going to try to override the Copier and make some adjustments to
> > work around this problem,
> > but there seems to be no way to do that (MergeService is final and
> > MergeService.getCopier() always
> > uses the EMFCompareEObjectCopier()).
> >
> > Any ideas on what we can do to get the MergeService to copy the
> > non-containment reference over?
> >
> > Thanks!
> >
> > --Stephen
>
>
>
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