[eclemma-dev] P2 metadata for smooth transition for users

[Evgeny Mandrikov <mandrikov@xxxxxxxxx>]

Hi guys,

First I'd like to let you know about progress: now we have automatic signing and publishing done by https://hudson.eclipse.org/eclemma/ to http://download.eclipse.org/eclemma/

And so I started work on subject of this email based on https://github.com/eclipse/m2e.wtp/blob/master/org.eclipse.m2e.wtp.feature/p2.inf as a reference. But must admit that I'm not fluent in tuning of P2 metadata. Even if this could magically "just work", I'm not in favor of doing modifications that can't explain, so below is p2.inf with some guesses based on meager info I could find:

# can update any "com.mountainminds.eclemma.feature" and previous versions of "org.eclipse.eclemma.feature"

update.matchExp = providedCapabilities.exists(pc | pc.namespace \=\= 'org.eclipse.equinox.p2.iu' && (pc.name \=\= 'com.mountainminds.eclemma.feature.feature.group' || pc.name \=\= 'org.eclipse.eclemma.feature.feature.group' && pc.version < '$version$'))

# requires additional IU described below

requires.0.namespace=osgi.bundle

requires.0.name=com.mountainminds.eclemma

requires.0.range=[$version$, $version$]

units.1.id=com.mountainminds.eclemma

units.1.version=$version$

units.1.singleton=true

units.1.provides.0.namespace=osgi.bundle

units.1.provides.0.name=com.mountainminds.eclemma

units.1.provides.0.version=$version$

# to not overwrite the main artifact, the additional IU should have classifier (https://bugs.eclipse.org/bugs/show_bug.cgi?id=430728)

units.1.properties.1.name=maven-classifier

units.1.properties.1.value=p2inf

# TODO explain

units.1.properties.0.name=org.eclipse.equinox.p2.name

units.1.properties.0.value=This version cannot be installed on top of the already installed EclEmma plugin. Uninstall the previous version and try the install again.

Could you please help me to understand last property and confirm/deny guesses?

Thanks.