[JENKINS-67000] Restore setting of null security manager

[jglick]

https://issues.jenkins.io/browse/JENKINS-67000

Reverts #481 pending a more nuanced fix.

[basil]

As a temporary hotfix, OK.

[timja]

Tbh once we drop Java 8 we can just revert this I think

[jglick]

once we drop Java 8 we can just revert this

Only if we remove JWS support as well. You can run IcedTea on Java 11.

[jglick]

Will leave it to someone who knows how to use the release bot to merge & release this. (Ironically, I think we could use regular JEP-229 for this component if it were not for the signature, which is only used by…JavaWebStart.)

[timja]

once we drop Java 8 we can just revert this

Only if we remove JWS support as well. You can run IcedTea on Java 11.

I doubt people are going to the hassle of setting that up just for this

[timja]

FTR we don't support it on Java 11 even with iced tea: https://github.com/jenkinsci/jenkins/blob/e27b310065b3c036b5fc9d123f1d1d99d3058c00/core/src/main/java/hudson/slaves/JNLPLauncher.java#L262-L265

[MarkEWaite]

@jeffret-b when you have reviewed this and decide to merge it, let me know and I can assist with the release machinery.

[jglick]

we don't support it on Java 11 even with iced tea

jenkinsci/jenkins#3766 indeed, which seems incorrect, not least because it is checking the version of Java running on the controller which is irrelevant in this context.

🤷 if we do not care to support IcedTea/OpenWebStart users on Java 11+, fine with me but ought to be a conscious decision mentioned in @MarkEWaite’s jenkinsci/jep#382. At the same time we should consider removing the JAR signature here, which (AFAIK) serves no function in non-JWS usages of remoting.jar and just complicates infrastructure; we can delete the GUI mode from remoting; and we can remove slave-installer and its implementations: https://github.com/jenkinsci/jep/blob/master/jep/230/README.adoc#marking-slave-installer-as-detached

[jeffret-b]

We really should remove the Launch button and all support for WebStart. They cause more confusion and bad behavior than they help. I've tried a couple of times in the past, but encountered some opposition based on unknown usage of the feature. The low level of interest in this regression indicates that this would be an overall gain and would negatively impact few people. We definitely should not carry WS forward into Java 11, even though it's possible. There's also no reason why we need to wait for Java 8 support termination before we take this step.

[jeffret-b]

Since this was an accidental regression, it's fine to restore this operation.

Ultimately, we really should remove it.

[jeffret-b]

Let's give this one the 24 hour waiting period for any additional comments or concerns.

[jeffret-b]

@MarkEWaite , can you perform a release when you have a chance?

[MarkEWaite]

@MarkEWaite , can you perform a release when you have a chance?

Release build 4.12 is complete and available on artifactory.

[MarkEWaite]

@jeffret-b could you publish the changelog from GitHub releases?