Re: [e4-dev] Re-exporting Require-Bundle

[Benjamin Muskalla <bmuskalla@xxxxxxxxxxxxxxxxx>]

Hi Eike,

first off: +1 for not re-exporting bundles.

See comments inline.

Eike Stepper wrote:
> If it 
> is part of the higher API, e.g. B publishes method signatures with 
> parameter types from A, then bundle A should be re-exported since it is 
> a pain for API B clients to recurse through all the non-explicit, 
> transitive dependencies.
I see your point that this is a real pain but in my eyes it is something 
which should be solved by better tooling support (Chris?) and not by 
reexporting the dependencies in the host bundle.

> In this particular case it seems as if dependencies (require-bundle) on 
> some EMF bundles raised the issue. I know that the APIs of EMF probably 
> belong to the most stable ones in Eclipse.
I don't think that it's about EMF in particular. It's always the same 
problem when you add API that doesn't belong to your specific bundle. I 
stumbled across so many places where a dependency could be removed 
because it was replaced with something else or was obsolete - but it was 
not possible as other bundles relied on the reexported dependency 
instead of having their own dependency. I think with a better tooling 
support in this case nobody would notice the difference. But we still 
have the advantage of not managing the reexports forever.

Cheers
  Ben

>  
> Thomas Watson schrieb:
> > +1
> >
> > Re-exporting is evil. I think it really dirties your bundle's API 
> > contract. Unless you use a real brittle version range on your 
> > require-bundle constraint you cannot be that confident that your API 
> > signature will remain constant for a particular version of you bundle. 
> > I would almost go as far as to say we should add a warning in PDE to 
> > flag any usage of re-export. I think it is simply a bad practice 
> > re-export bundles. The problem is once you have added re-export you 
> > cannot remove it without it being considered a breaking API change. 
> > This would be equivalent to removing API from your bundle.
> >
> > Tom
> >
> >
> >
> > Inactive hide details for John Arthorne ---06/11/2009 04:22:57 PM---I 
> > noticed org.eclipse.e4.ui.model.workbench re-exports a coJohn Arthorne 
> > ---06/11/2009 04:22:57 PM---I noticed 
> > org.eclipse.e4.ui.model.workbench re-exports a couple of EMF plug-ins. 
> > As a general reminder, re-exporting should be
> >
> >
> > From: 	
> > John Arthorne <John_Arthorne@xxxxxxxxxx>
> >
> > To: 	
> > e4-dev@xxxxxxxxxxx
> >
> > Date: 	
> > 06/11/2009 04:22 PM
> >
> > Subject: 	
> > [e4-dev] Re-exporting Require-Bundle
> >
> > ------------------------------------------------------------------------
> >
> >
> >
> >
> > I noticed org.eclipse.e4.ui.model.workbench re-exports a couple of EMF 
> > plug-ins. As a general reminder, re-exporting should be avoided if 
> > possible, since it means you are essentially publishing the entire API 
> > of that other bundle as part of your bundle, and committing to 
> > maintaining that re-exported content indefinitely. Avoiding re-export 
> > generally gives more flexibility to remove or refactor dependencies in 
> > the future without breaking the API exposed by your plug-in. Does 
> > anyone know of a particular reason for the re-exports in this case? If 
> > I don't hear back, I'll make an attempt at fixing this to avoid 
> > re-export._______________________________________________
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> > e4-dev@xxxxxxxxxxx
> > https://dev.eclipse.org/mailman/listinfo/e4-dev
> >
> >
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