Jenkins Pipeline Groovy script not executing in workspace

Question

I have a Jenkins that runs in a container. I was trying to debug a groovy file that is running in Jenkins pipeline and found out it is not executing from the workspace for some reason. Below is the Jenkins pipeline

pipeline {
    agent any

    stages {
        stage('testing') {
            steps {
                script {
                    sh '''
                    ls
                    '''
                    def proc = [ "ls"].execute()
                    def output = proc.text
                    println(output)
                }
            }  
        }

    }
}

The shell command returns listing of the checked out repository, as expected. However same command executed in groovy script shows container root filesystem. That's not what I expected. What is going on here?

Pipeline] }
[Pipeline] // stage
[Pipeline] withEnv
[Pipeline] {
[Pipeline] stage
[Pipeline] { (testing)
[Pipeline] script
[Pipeline] {
[Pipeline] sh
+ ls
README.md
docs
jenkins
modules
scripts
[Pipeline] echo
aws
bin
boot
dev
etc
home
lib
lib64
media
mnt
opt
proc
root
run
sbin
srv
sys
tmp
usr
var
vault

Answer 1

The sh node is a proper Jenkins built-in step that runs the command in the job.

The .execute() is a bit of a hack:)
You're running the Groovy script through the Jenkins interpreter, which is not pretty standard and does it's own thing.

I'd avoid it and keep with the Jenkins sh that has a standard behaviour.