get_last_branch.groovy

// this script will reuse GIT_BRANCH variable from the last successful job, if current BRANCH parameter is empty

def branch="$BRANCH"

println "currentJob --> ${currentJob}"
println "currentBuild --> ${currentBuild}"

if (branch=="") {
   try {
      println "setting BRANCH from the last build"
      def lastBuild = currentJob.lastSuccessfulBuild
      println "lastBuild -> ${lastBuild}"
      //branch = lastBuild.getBuildVariables().get("BRANCH");
        def git_branch = lastBuild.envVars['GIT_BRANCH']
         branch = git_branch.split('/',2)[1]
      } catch (error) {
          println "ERROR -> ${error}"
          branch=""
      }  
}

println "currentBranch --> ${branch}"
def map = [BRANCH: "${branch}"]
return map