Oleg has it. We have been burnt many times by all of the
characteristics outlined. Look up "spawn of the devil" and you will
see a reference to reexporting bundles ;-)
Jeff
Oleg Besedin wrote:
+1 for not re-exporting.
In addition to evils of re-exporting
that John and Tom described, I strongly believe that E4 UI should not
leak
EMF artifacts through its APIs.
Thanks,
Oleg
-1
Some time ago there was already a long discussion about re-exporting
pros
and cons. Unfortunately I can't remember pointers to it.
Here my 2 cents:
IMHO it depends mostly on whether the API of the referenced bundle A is
an integral part of the API of the referencing bundle B, or not. 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.
The question if it's a good idea to put A-types into the B-API is a
separate
discussion. But I think sometimes it's convenient and sometimes it's
necessary.
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. And usually code that
depends
on these EMF APIs will never even want to drop this dependency. So, in
the end I think that the two the main arguments *against* re-exporting
dependencies don't count so much if we talk particularly about
dependencies
on EMF ;-)
Cheers
/Eike
----
http://thegordian.blogspot.com
http://twitter.com/eikestepper
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
 John
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
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
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