Backport #1660 to 2.7.5 and 3.0?

[Bananeweizen]

I've just been checking how much slower target resolution is due to the relative path issue from #1660. I have a multi module project at work, where the difference is several minutes (!!) on my laptop. That's because

• 50 modules
• the target contains 2 further nested targets
• one of the nested targets contains 30 Maven artifacts, of those several are automatically wrapped by Tycho

That all multiplies, so Tycho basically resolves 150 targets instead of 3 and wraps some hundred Maven artifacts for no good. I've meanwhile found a workaround by exchanging ${basedir}/../somedir/my.target with ${maven.multiModuleProjectDirectory}/somedir/my.target, so I can live without a backport. Nevertheless there might be others affected by similar slowdowns (if they use maven artifacts in their targets). Therefore this might be a good candidate for backporting to the older versions.

[laeubi]

I have added a section about backporting to the contributing guide now:
https://github.com/eclipse-tycho/tycho/blob/master/CONTRIBUTING.md#backporting

@Bananeweizen do you like to drive the backporting steps for this (and possibly other items as well?).

[lppedd]

I would like to coordinate with @Bananeweizen to include #1625 and #1681, if possible.

[laeubi]

Just let you know that we prepare a 3.0.1 snapshot. Because there is a major problem to fix, we won't have much time and won't have a test-period, but trivial fixes can be included as of 12:00 GMT+1:00 if offered by a sucessful PR against the tycho 3.0.x branch.

[laeubi]

@Bananeweizen @lppedd we have already some fixes for 3.0.2 and probably there is an opportunity to perform a new release soon, so if you like to get your changes included it would be good to just start with that, just leave a note if you are working on a backport here should be enough for coordination.