[platform-update-dev] (no subject)

[Dorian Birsan <birsan@xxxxxxxxxx>]

We have been doing some simplification
of the update/install component, mostly in the UI and some code refactoring
for supporting command driven operations, and now we're investigating the
update API's, including the xml specs.

One item that seems to play a major
role in the increased complexity (code-wise and the number of bugs associated
with it) is the <include> feature relationship. The include relationship
has been introduced to allow features to be built out of existing features,
as opposed to having to always list all the plugins needed. The final plugin
list is obtained by transitive closure.
However, in Eclipse 2.1 <include>
was no longer a strict include, it allowed more flexibility by using the
"match" attribute:
http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/platform-update-home/doc/working/feature_extensions_2.html

One main reason was to allow updating
of nested features independently of parents, and another reason was to
allow feature patching.

We would like to go back to the previous
direct include (no "match" attribute) and address the two reason
differently:
- treat <include> as ownership
and do not allow nested features to be updated independently of the parent
features
- patches will no longer include features,
but only plugins. A patch will be associated with a root feature, and contain
plugins from any nested feature. A patch should also be able to <include>
other patches.
- if you have a need for a nested feature
needs to be updated independently of its parent, then don't use <include>
for it, but make it an imported feature, with the appropriate match attribute.
- in addition, we are playing with the
idea of a policy file that determines what can and can't be updated, and
from what update sites.

Please post any comments about the proposed
changes and, if they are breaking changes, please describe your scenarios.

Thanks,
-Dorian