[FIXED JENKINS-42382] Add PATH+ANT to buildEnvVars(...)

[abayer]

JENKINS-42382

This ensures that Ant's bin directory ends up on the PATH when using
the Pipeline tool step. Note that Jenkins' environment variable
management will handle converting "/bin" on Windows if needed, we do
not need to do that explicitly.

cc @reviewbybees esp @armfergom

[reviewbybees]

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[jglick]

This really ought to get test coverage, especially if you claim this is a regression.

[abayer]

@jglick It's not a regression - fixed the JIRA to be an improvement.

[jglick]

That is not what we actually care about. We want to know if a full environment, once expanded, contains a PATH which starts with the new dir.

[abayer]

Isn't that already established enough in core? Legitimately wondering here - such a test would not be testing anything specific to Ant, it'd be testing core's PATH+FOO logic, which is already covered in https://github.com/jenkinsci/jenkins/blob/master/core/src/test/java/hudson/EnvVarsTest.java#L51-L69

[jglick]

Of course core unit-tests that behavior, but this would be proving that the purported fix actually has some effect: that the method you are overriding is called when you think it is, etc.

[abayer]

I'll be blunt - I don't think that's necessary. If buildEnvVars results in PATH+ANT being included, that seems sufficient to me, since we know that buildEnvVars gets called and that PATH+FOO in EnvVars gets added to the PATH.

[jglick]

OK. Can I assume you are doing at least manual testing?

pipeline-model-definition could add a test-scoped dep on this and do a full integration test there, if you also add a test dep on jenkins-test-harness-tools.

[abayer]

Yup, did manual testing, and I'd happily add a test in pipeline-model-definition.