Stop persisting deprecated artifactoryServers on serialization

[basil]

See JENKINS-65687. Amends #455, which broke JCasC export. Fixes this regression by marking the deprecated artifactoryServers field with transient, which causes XStream not to serialize the (already migrated!) field as described in the Jenkins developer documentation.

(Note that the common convention in Jenkins plugins is to perform such migration logic in an XStream readResolve() method, as described in the above developer documentation, but the JFrog Artifactory plugin does this in a dedicated ArtifactoryBuilderConverter class.)

[timja]

Have you got time to add a test here @basil? To stop this happening again?

[basil]

I don't have the time, but I agree that this would be a useful action item for the maintainers of this plugin.

[Or-Geva]

Thank you @basil for this contribution!. We appreciate your time and effort.
However, doesn't Jenkins-Artifactory-Plugin 3.11.2 remedy JENKINS-65687 issue?.

[basil]

However, doesn't Jenkins-Artifactory-Plugin 3.11.2 remedy JENKINS-65687 issue?.

If it does, then JENKINS-65687 was not updated to indicate a resolution.

[Or-Geva]

@basil, according to your input, do we still need this fix?

[basil]

I suggest you read the the Jenkins developer documentation I linked to in the PR description. Yes, this fix is needed to delete the old <artifactoryServers> section from org.jfrog.hudson.ArtifactoryBuilder.xml after the migration takes place.

[Or-Geva]

Thanks for the response @basil.
If we do merge this now, the old configuration will get deleted, and as a result, a downgrade back to an older version wouldn't be possible. This will affect everyone, include users who don't use JCasC

[basil]

The Jenkins project generally does not support downgrades. In general it is expected that upgrades may perform irreversible data migration and that users who wish to be able to downgrade should back up their Jenkins home directory prior to upgrading.

[eyalbe4]

@basil,
Maybe we can postpone this change a bit, to allow people who do want to downgrade,.to do so. Once we're sure the new functionality is 100% bullet proof, we'll go ahead and implement this cham.
Release 3.11.0 included a complete rewrite of the Artifactory client.

[basil]

@basil, Maybe we can postpone this change a bit, to allow people who do want to downgrade,.to do so. Once we're sure the new functionality is 100% bullet proof, we'll go ahead and implement this cham.

But 7 months later?