Inconsistent build-qualifier computation between goals tycho-packaging-plugin:build-qualifier and package-feature

[HannesWell]

The goals and tycho-packaging-plugin:build-qualifier and tycho-packaging-plugin:package-feature seem to have a different logic how to compute/obtain the build-qualifier of a plugin included in a feature with respect to merged git-branches.

The build-qualifier goal seems to consider the paths via both parent-git-commits of a merge-commit when computing the latest time a Plug-in was touched by a commit, while the package-feature goal seems to consider only one parent/path (in my case only the second one). But maybe the build-qualifier goal just takes the other one and is 'right' by chance in this case.

This can lead to errors like the following where the dependency of a feature to a plug-in cannot be resolved during the assembly of the repository:

[INFO] --- tycho-p2-repository-plugin:2.6.0:assemble-repository (default-assemble-repository) @ org.eclipse.m2e.site ---
[INFO] {osgi.os=win32, osgi.ws=win32, org.eclipse.update.install.features=true, osgi.arch=x86_64}
[ERROR] Cannot resolve project dependencies:
[ERROR]   Software being installed: org.eclipse.m2e.site raw:1.16.0.'SNAPSHOT'/format(n[.n=0;[.n=0;[-S]]]):1.16.0-SNAPSHOT
[ERROR]   Missing requirement: org.eclipse.m2e.feature.feature.group 1.19.2.20220121-2010 requires 'org.eclipse.equinox.p2.iu; org.eclipse.m2e.sourcelookup [1.17.5.20220120-2044,1.17.5.20220120-2044]' but it could not be found
[ERROR]   Cannot satisfy dependency: org.eclipse.m2e.site raw:1.16.0.'SNAPSHOT'/format(n[.n=0;[.n=0;[-S]]]):1.16.0-SNAPSHOT depends on: org.eclipse.equinox.p2.iu; org.eclipse.m2e.feature.feature.group 0.0.0

The version required by the feature is 1.17.5.20220120-2044 while that plug-in is build with version 1.17.5.20220121-0829:

[INFO] ------------< org.eclipse.m2e:org.eclipse.m2e.sourcelookup >------------
[INFO] Building [bundle] M2E Source Lookup Core 1.17.5-SNAPSHOT         [23/53]
[INFO] ---------------------------[ eclipse-plugin ]---------------------------
[INFO] 
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ org.eclipse.m2e.sourcelookup ---
[INFO] 
[INFO] --- tycho-packaging-plugin:2.6.0:build-qualifier (default-build-qualifier) @ org.eclipse.m2e.sourcelookup ---
[INFO] The project's OSGi version is 1.17.5.20220121-0829

The Git-History looks like the following and the build was performed with the currently checkout branch guavaOld:

On the master branch the affected plug-in was last touched with commit 7a6f149 on the branch being built that plug-in was last touched with commit 43cc2ad:

What's interesting is that the feature.xml file written to the feature-project's target folder (in this case org.eclipse.m2e.feature\target\feature.xml) contains the correctly expanded versions, but in the jar file created next to it the feature.xml has the wrong version of the included plug-in. So it looks like the mistake is happening in the packing step.

[laeubi]

Just wondering, do you do an incremental build (mvn install) or do you ensure its a full build (mvn clean install)?

[HannesWell]

After continuing my debugging it looks like the tycho-p2-plugin:p2-metadata is the cause in this case

[INFO] tycho-p2-plugin:2.6.0:p2-metadata-default (default-p2-metadata-default) org.eclipse.m2e.feature ---
[WARNING] MavenProject: org.eclipse.m2e:org.eclipse.m2e.feature:1.19.2-SNAPSHOT @ C:\dev\git\eclipse.m2e-core\org.eclipse.m2e.feature\.polyglot.feature.xml: baseline and build artifacts have same version but different contents
   no-classifier: different
      META-INF/ECLIPSE_.RSA: present in baseline only
      META-INF/ECLIPSE_.SF: present in baseline only
      feature.xml: different
      p2.inf: different

[INFO] MavenProject: org.eclipse.m2e:org.eclipse.m2e.feature:1.19.2-SNAPSHOT @ C:\dev\git\eclipse.m2e-core\org.eclipse.m2e.feature\.polyglot.feature.xml
    The main artifact has been replaced with the baseline version.

In the m2e-build on the Jenkins server, that is affected here, the p2-metadata goal is used instead of p2-metadata-default but the effect is the same.

While the replacement of the m2e.feature actually makes sense (it was not touched in the meantime), although it leads to the described errors, I wonder why the replacement does not happen if all changes are squashed on top of the current master?
Not replacing the feature-jar is the correct behavior in this case but the logic that prevents the replacement seems to not consider merged branches.

[HannesWell]

Just wondering, do you do an incremental build (mvn install) or do you ensure its a full build (mvn clean install)?

I do a full build mvn clean verify.

[laeubi]

You need to increment the feature version as well if you increment a bundle version, this is not the tycho-p2-plugin:p2-metadata plugin but the baseline replace mojo.

[HannesWell]

You need to increment the feature version as well if you increment a bundle version, this is not the tycho-p2-plugin:p2-metadata plugin but the baseline replace mojo.

But I did not increment the bundle version. It was incremented in the commit before (7a6f149), but since there was no release in-between I did not have to increment it. The feature version was incremented longer before both commits, but there was also no release since then. I think this is fine.

I think the problem here is that due to other commits that were pushed on the master-branch in the meantime a newer version of the feature (in terms of build-qualifier) is available in the base-line repo. And because there was no other commit on the branch that touches anything that would affect the features build-qualifier, the feature version is driven by that other commits change. So the feature is correctly replaced by the base-line version since it has the exact same version (including build-qualifier) as the one in the baseline. But that baseline-version of the feature contains the wrong build-qualifier of the plugin.

So it looks like everything works as expected. However I have the impression that the baseline replacement performed by the tycho-p2-plugin:p2-metadata plugin does not work well with a GitHub workflow where one performs merges on a branch. In this case force pushes avoid this problem.

[laeubi]

Tycho tycho-p2-plugin:p2-metadata plugindos not do the replacement as far as I know, this "replace with baseline" is something specifically requested by the m2e pom and not tycho standard behavior.

[HannesWell]

Tycho tycho-p2-plugin:p2-metadata plugindos not do the replacement as far as I know, this "replace with baseline" is something specifically requested by the m2e pom and not tycho standard behavior.

It looks like it actually is the default behavior of the tycho-p2-plugin:p2-metadata plugin. The field baselineReplace of P2MetadataMojo defaults to all. About all the doc says:
(default): Replace build artifacts with baseline version. Attached artifacts only present in the build are removed.