I'm trying to use the lock() option in an options block of a stage. I want the lock resource to be dynamic (depending on an environment variable).

For example:

    environment  {
        BRANCH_TO_USE = get_branch_to_use()
    }
stages {
    stage('Lock build'){
        options {
          lock(resource: "lock-${env.BRANCH_TO_USE}", quantity: 1)
        }
        stages {
...

But the resulting string is always "lock-null". I tried it without "env." but to no avail.

I would expect this to work especially since the environment variable is available in the coming stages with no problem.

Is there a way to support this or a possible workaround?