[JEP-230] [JENKINS-55582] Skip detached-plugins (was: pretest core with detached instance-identity)

[jglick]

Unlike #1159 this is not actually reflecting instance-identity as a new managed plugin; it is just checking how much the core change in isolation breaks existing tests.

[jglick]

#1159 (comment)

[jglick]

So https://github.com/jenkinsci/bom/pull/1160/checks?check_run_id=6715569819 for example is curious. The test output makes it clear that the failure ultimately is from

java.lang.NoClassDefFoundError: org/jenkinsci/main/modules/instance_identity/InstanceIdentity

and I can reproduce the failure locally

PLUGINS=support-core TEST=AboutJenkinsTest bash local-test.sh 

And yet

mvn -f target/local-test/pct-work/support-core clean test -Djenkins.version=2.349-rc32398.3b_263b_c6b_8a_3 -Dtest=AboutJenkinsTest\#testAboutJenkinsContent

passes:

INFO	hudson.PluginManager#considerDetachedPlugin: Loading a detached plugin as a dependency: …/target/local-test/pct-work/support-core/target/tmp/jenkins…/plugins/instance-identity.jpi

In the plain source tree, but not when jenkins.version is overridden, org.jenkins-ci.modules:instance-identity:jar:2.2:test is in the dependency tree via jenkins-war. The test fails only when jth.jenkins-war.path is passed, I suspect due to the lack of the detached plugin

bom/prep.sh

Line 35 in a7ea532

rm -rfv megawar-$LINE/WEB-INF/detached-plugins megawar-$LINE/META-INF/*.{RSA,SF}

[jglick]

FTR this behavior dates to 6c00be1 because of jenkinsci/plugin-compat-tester#116 (comment) which was three years ago and I barely recall what the issue was.

[basil]

Good result with tip-of-trunk core, which gives confidence in the forthcoming weekly release. Now let's see if this PR works on the existing weekly release, in which case why not merge it to unblock other work?

[basil]

Since we'll need this on Tuesday when 2.357 ships, but since it doesn't cause any harm on 2.356, let's just merge it now to be able to test other incremental builds of 2.357-SNAPSHOT in the meantime between now and Tuesday.