Intermittent Y-build failures due to baseline replacement

[HannesWell]

As reported in #2791 (comment) and already noticed before the Y-build fails occasionally with failures similar to

[2025-01-28T15:15:52.984Z] [ERROR] Cannot resolve dependencies of project eclipse.platform.releng.tychoeclipsebuilder:equinox-sdk:eclipse-repository:4.35.0-SNAPSHOT
[2025-01-28T15:15:52.984Z] [ERROR]  with context {osgi.os=linux, osgi.ws=gtk, org.eclipse.update.install.features=true, org.eclipse.jdt.buildtime=true, osgi.arch=x86_64, org.eclipse.update.install.sources=true}
[2025-01-28T15:15:52.984Z] [ERROR]   Software being installed: org.eclipse.equinox.sdk.product 4.35.0.qualifier
[2025-01-28T15:15:52.984Z] [ERROR]   Missing requirement: org.eclipse.equinox.sdk.feature.group 3.23.1600.v20250127-1848 requires 'org.eclipse.equinox.p2.iu; org.eclipse.jdt.core.compiler.batch [3.41.0.v20250122-1644,3.41.0.v20250122-1644]' but it could not be found
[2025-01-28T15:15:52.984Z] [ERROR]   Cannot satisfy dependency: org.eclipse.equinox.sdk.product 4.35.0.qualifier depends on: org.eclipse.equinox.p2.iu; org.eclipse.equinox.sdk.feature.group 0.0.0: See log for details
[2025-01-28T15:15:52.984Z] [ERROR] -> [Help 1]

after baseline replacement detected changes without a qualifier change:

[2025-01-28T15:14:21.229Z] [WARNING] MavenProject: org.eclipse.equinox:org.eclipse.equinox.sdk:3.23.1600-SNAPSHOT @ /home/jenkins/agent/workspace/YPBuilds/Y-build-4.35/cje-production/gitCache/eclipse.platform.releng.aggregator/equinox/features/org.eclipse.equinox.sdk/.polyglot.feature.xml: baseline and build artifacts have same version but different contents
[2025-01-28T15:14:21.229Z]    no-classifier: different
[2025-01-28T15:14:21.229Z]       feature.xml: different
[2025-01-28T15:14:21.229Z] 
[2025-01-28T15:14:21.229Z] [INFO] MavenProject: org.eclipse.equinox:org.eclipse.equinox.sdk:3.23.1600-SNAPSHOT @ /home/jenkins/agent/workspace/YPBuilds/Y-build-4.35/cje-production/gitCache/eclipse.platform.releng.aggregator/equinox/features/org.eclipse.equinox.sdk/.polyglot.feature.xml
[2025-01-28T15:14:21.229Z]     The main artifact has been replaced with the baseline version.

A similar report was #2660 and looking at #2660 (comment) the reason could indeed be that the Y-build uses the I-build as baseline for the p2-baseline-replacement:

eclipse.platform.releng.aggregator/eclipse-platform-parent/pom.xml

Line 85 in c077b24

<comparator.repo>https://download.eclipse.org/eclipse/updates/4.35-I-builds</comparator.repo>

If then there is no change on the BETA_JAVAX branch between the latest I-build and the next Y-build then the scenario could happen as the baseline contains more recent artifacts than the reactor (qualifier-wise).
I have to investigate it again, but if that's really the cause a solution would be to baseline Y-builds against the latest Y-build repo by specifying -Dcomparator.repo=https://download.eclipse.org/eclipse/updates/4.35-Y-builds/.
This would hopefully also resolve the comparator-errors that are currently found on all (otherwise successful) Y-builds.

Another reason might be that there is a problem in considering time-zones during baseline replace or when computing aggregated qualifiers for features. The former seems to be a much better explanation of the problem, but IIRC I have also seen problems that seem to be connected to the latter (i.e. baseline-replacements failing shortly after I-builds), but this was already some time ago, so could be a red herring.

[HannesWell]

@stephan-herrmann with #2800 this should now be fixed. The next Y-build should confirm this if there are no comparator-errors.

Btw. are you aware of the existing comparator-errors between the I-build repo?
https://download.eclipse.org/eclipse/downloads/drops4/Y20250131-1000/buildlogs/comparatorlogs/buildtimeComparatorUnanticipated.log.txt

Comparator differences from current build
	/home/jenkins/agent/workspace/YPBuilds/Y-build-4.35/cje-production/siteDir/eclipse/downloads/drops4/Y20250131-1000
compared to reference repo at 
	https://download.eclipse.org/eclipse/updates/4.35-I-builds

1.  eclipse.platform/runtime/bundles/org.eclipse.e4.core.di/.polyglot.META-INF
   no-classifier: different
      org/eclipse/e4/core/internal/di/AnnotationLookup.class: different
    The main artifact has been replaced with the baseline version.
    The following attached artifacts have been replaced with the baseline version: [sources]

2.  eclipse.pde/apitools/org.eclipse.pde.api.tools.tests/pom.xml
   no-classifier: different
      org/eclipse/pde/api/tools/util/tests/UtilTests.class: different
    The main artifact has been replaced with the baseline version.
    The following attached artifacts have been replaced with the baseline version: [sources]

This means that we will probably have these errors in the I-build if the new ECJ version is merged into master. But maybe the change in generated byte-code is intended. Just wanted to make you aware. :)

[stephan-herrmann]

Btw. are you aware of the existing comparator-errors between the I-build repo?

Thanks for the heads-up.

Initial analysis indicates the change should be legit, but I asked for confirmation via eclipse-jdt/eclipse.jdt.core#3649