Bump org.eclipse.equinox.p2.core to 2.12.0

[merks]

Fixes #514

[github-actions]

Test Results

  250 files   -   125    250 suites   - 125   27m 25s ⏱️ - 15m 27s
1 893 tests ±    0  1 890 ✅ ±    0  3 💤 ±0  0 ❌ ±0 
4 451 runs   - 2 228  4 445 ✅  - 2 225  6 💤  - 3  0 ❌ ±0 

Results for commit 43392e4. ± Comparison against base commit b46100f.

♻️ This comment has been updated with latest results.

[iloveeclipse]

Looking on dependencies of the new API, following bundles should enforce new version:

• org.eclipse.equinox.p2.metadata.repository
• org.eclipse.equinox.p2.ui.sdk.scheduler

[merks]

I won't have time for further changes after my 13 hour day. If you feel they are necessary, you or someone else will need to make such changes. Sorry.

[iloveeclipse]

I won't have time for further changes after my 13 hour day.

You shouldn't push a PR after 8 hours day in the first place :-)

If you feel they are necessary

Yes, otherwise we may run into issues if people get "partial" p2 updates.

I've updated your patch with required changes.

[iloveeclipse]

org.eclipse.equinox.p2.core;version="[2.12.0,2.13.0]" ???

Why do we import same package we provide? Is this something that can be provided by others???

[iloveeclipse]

Actually the change uses wrong range, was meant to excluding 2.13 but is including.

[HannesWell]

Why do we import same package we provide? Is this something that can be provided by others???

Importing exported packages is considered good OSGi practice by many:
https://felix.apache.org/documentation/tutorials-examples-and-presentations/apache-felix-osgi-faq.html#import-own-exports
I have not yet seen the necessity of that for Eclipse, but I have also not thought about it in great depth.

[iloveeclipse]

Interesting (and unrelated) error on Mac

Failed to execute goal org.eclipse.tycho:tycho-apitools-plugin:4.0.8-SNAPSHOT:verify (verify) on project org.eclipse.equinox.p2.discovery: 
Execute ApiApplication failed: InvocationTargetException: 
Cannot load from object array because "this.this$0.fIndexedDetectors" is null -> [Help 1]

Shouldn't be the problem caused by this PR.

[iloveeclipse]

Actually the change uses wrong range, was meant to excluding 2.13 but is including.

[iloveeclipse]

Something is wrong with API tooling:

[ERROR] Failed to execute goal org.eclipse.tycho:tycho-apitools-plugin:4.0.8-SNAPSHOT:verify (verify) on project org.eclipse.equinox.p2.reconciler.dropins: Execute ApiApplication failed: InvocationTargetException: Error reading manifest for /home/jenkins/agent/workspace/p2_PR-516/.m2/repository/p2/osgi/bundle/org.sat4j.pb.source/2.3.6.v20201214/org.sat4j.pb.source-2.3.6.v20201214.jar: zip file is empty