handle null retention policy resulting from direct xml pod template i…

[gabemontero]

…njection (seen during agent termination)

Fixes https://issues.jenkins-ci.org/browse/JENKINS-53260

@carlossg ptal

@bparees @adambkaplan fyi

[bparees]

lgtm

[Vlatombe]

I think a better fix would be to add the default pod retention policy upon deserialization in

kubernetes-plugin/src/main/java/org/csanchez/jenkins/plugins/kubernetes/PodTemplate.java

Lines 628 to 644 in ecc2312

	protected Object readResolve() {
	if (containers == null) {
	// upgrading from 0.8
	containers = new ArrayList<>();
	ContainerTemplate containerTemplate = new ContainerTemplate(KubernetesCloud.JNLP_NAME, this.image);
	containerTemplate.setCommand(command);
	containerTemplate.setArgs(Strings.isNullOrEmpty(args) ? FALLBACK_ARGUMENTS : args);
	containerTemplate.setPrivileged(privileged);
	containerTemplate.setAlwaysPullImage(alwaysPullImage);
	containerTemplate.setEnvVars(envVars);
	containerTemplate.setResourceRequestMemory(resourceRequestMemory);
	containerTemplate.setResourceLimitCpu(resourceLimitCpu);
	containerTemplate.setResourceLimitMemory(resourceLimitMemory);
	containerTemplate.setResourceRequestCpu(resourceRequestCpu);
	containerTemplate.setWorkingDir(remoteFs);
	containers.add(containerTemplate);
	}

[bparees]

@adambkaplan did @gabemontero catch you up on this?

[gabemontero]

I did @bparees though we had left it that this was done ... I'll see about driving this to closure

At first blush @Vlatombe 's suggestion should work as well

I'll verify why we presumably wait on @carlossg to decide which way he wants to go

[gabemontero]

Confirmed updating the deserialization path also works

pushed a second comment with that in place and the prior fix commented out

I'll squash / clean up / uncomment code as needed based on where the consensus lands after @carlossg chimes in.

thanks

[gabemontero]

bump @carlossg ... see #381 (comment) for latest status