[FIXED] Jenkins: remove specific parameter from pipeline if it's empty

Issue

In a generic pipeline I have the following:

pipeline {
    agent any
    parameters {
        string(name: "TEST_VAR", description:  "testvar")
    }
    stages {
        stage("My stage") {
            agent {
                docker {
                    image 'myimage'
                    args "-u root:root"
                }
            }
            steps {
                script {
                    params.each {param -> 
                        if (param.value == "") { sh "unset ${param.key}" }
                    }
                    sh 'printenv'
                }
            }
        }
    }
}

However, even if I leave the parameter empty, the printenv step prints TEST_VAR as an existing empty environment variable, as if the unset step did not work. How can I properly unset it, so that it's not declared at all?

Solution

As it turns out, jenkins parameters are immutable. I solved this issue by having the parameter called TEST_VAR_PARAM and then checking if it was empty and creating a TEST_VAR env value from its value.

Answered By - ihatenginx