org.eclipse.jkube.enricher.generic.ImageEnricher#mergeEnvVariables causes error for empty env variables

[mcarlett]

Describe the bug

Given a xml configuration in the plugin including empty env variable, the variable is read as null value and it causes

Execution default of goal org.eclipse.jkube:openshift-maven-plugin:1.17-SNAPSHOT:resource failed: Cannot invoke "String.equals(Object)" because the return value of "io.fabric8.kubernetes.api.model.EnvVar.getValue()" is null

Eclipse JKube version

SNAPSHOT

Component

JKube Kit

Apache Maven version

3.8.4

Gradle version

None

Steps to reproduce

1. in pom.xml configuration

<configuration>
 <resources>
   <env>
     <JAVA_OPTS_APPEND></JAVA_OPTS_APPEND>
   </env>
  </resources>
</configuration>

2. run oc:resource
   mvn oc:resource

Expected behavior

I'm expecting that the empty env variable can be considered as empty string instead of null or the null is managed in the line where the error is thrown

Runtime

OpenShift

Kubernetes API Server version

other (please specify in additional context)

Environment

Linux

Eclipse JKube Logs

No response

Sample Reproducer Project

No response

Additional context

Kubernetes Version: v1.29.5

the line https://github.com/eclipse-jkube/jkube/blob/master/jkube-kit/enricher/generic/src/main/java/org/eclipse/jkube/enricher/generic/ImageEnricher.java#L295

} else if (!newEnvVar.getValue().equals(oldEnvVar.getValue())) {

will cause the error, since newEnvVar.getValue() is null