[declarative pipeline] Variable persistance after Jenkins restart

[Bill Dennis]

Hi -

I have an issue with variables being restored in a pipeline job after a Jenkins restart.

Say I have a pipeline like this:

// Local var set to 'env'
def localEnv = env

// Simple local var
def foo = "Bar"

pipeline {
    agent any
   
    environment {
       
        // You can do it here but I really want the whole env in my own var
        myBuildNumber = "${env.BUILD_NUMBER}"
    }
   
    stages {
       
        stage('Init') {
           
            steps {
                echo "${localEnv.BUILD_NUMBER}"    
            }
        }
       
        stage('Hello') {
            steps {
               
                echo "hello"
               
                input 'Waiting for input...'
               
                // Lets see what we have
                echo "localEnv.BUILD_NUMBER = ${localEnv.BUILD_NUMBER}"
                echo "env.BUILD_NUMBER = ${env.BUILD_NUMBER}"
                echo "foo = ${foo}"
                echo "myBuildNumber = ${myBuildNumber}"
            }
        }
    }
}

I am making my own local variable as copy of the 'env' variable (localEnv). I do this a lot in my jobs because I call custom library DSL-type structure similar to this:

myCustomThing {
   reference = localEnv.BUILD_NUMBER
   message = "Something about build ${localEnv.BUILD_NUMBER}"
}

If I use 'env' there, I get a null pointer exception on this closure - something to do with groovy Closure delegate (that is another question I guess), so I did this 'def localEnv = env' thing to get around that. Anyway, for the normal case my job above outputs this after selecting approve on the input and all is well:

Waiting for input...

Proceed or Abort

Approved by Bill Dennis

[Pipeline] echo

localEnv.BUILD_NUMBER = 21

[Pipeline] echo

env.BUILD_NUMBER = 21

[Pipeline] echo

foo = Bar

[Pipeline] echo

myBuildNumber = 21

When I restart Jenkins while the input is waiting then approve the input the output is like this (note the null):

Waiting for input...

Proceed or Abort

Resuming build at Mon Mar 27 23:48:21 UTC 2017 after Jenkins restart

Ready to run at Mon Mar 27 23:48:32 UTC 2017

Approved by Bill Dennis

[Pipeline] echo

localEnv.BUILD_NUMBER = null

[Pipeline] echo

env.BUILD_NUMBER = 22

[Pipeline] echo

foo = Bar

As can be seen, 'localEnv.BUILD_NUMBER' comes back as null after the Jenkins restart. So it looks like I need to do a deep-copy of the 'env' or set up many more variables in my environment section for everything that needs to be available from 'env' surviving a restart, so that things I need cans be passed to any of my shared library stuff. 

Does anyone have any deeper understanding of this?

Thanks,

--Bill