Jenkins Pipeline and stash Pull Request Builder not working on PR create/update Below is the requirement needed to achieve using the Jenkins Pipeline and i am new bee into Jenkins Pipeline.

After completing development work and pushing his changes to
Bitbucket the user creates a pull request.
In order to approve a pull request we require at least one successful
Jenkins build. Thereby we would like to get only the build result of
the code checked in for the pull request.
When a pull request is created/updated Jenkins shall be triggered
automatically for real continuous integration.
The build result shall be reported back to Bitbucket.

Used Stash Pull Request Builder and stash Notifier for the above process which is working for Normal Freestyle Project.
We need to migrate the similar functionality using Jenkins pipeline, So have created the jenkins job as below.

The pipeline script to checks out the PR branch and trigger build is as below
node {
    stage('Checkout') {         
        checkout(
        [
            $class: 'GitSCM',
            extensions: [               
                [$class: 'CleanCheckout'],              
            ],
            branches: [
                [name: '']
            ], 
            userRemoteConfigs: 
            [[
                credentialsId: 'id', 
                url: 'repourl.git'
                refspec: ('+refs/pull-requests/*/from:refs/remotes/origin/pr/*/from'), 
                branch: ('origin/pr/${pullRequestId}/from')
            ]]
        ])
    }

    stage('Build') {    
        sh 'make'
    }
    stage('notify') {
    step([$class: 'StashNotifier'])
        try {
            // Do stuff
            currentBuild.result = 'SUCCESS'     
        } catch(err) {
            currentBuild.result = 'FAILED'
        }
    step([$class: 'StashNotifier'])
   }

}

Though i have done the above configuration when i create/update the PR, the build is not automatically triggered in jenkins. I guess the notification from stash to jenkins did not happen because we specify &quot;origin/${pullRequestId}/from&quot; in free style project. But i do not have that option to specify in pipeline job.
Tried few alternatives as below.
Instead of stash Pull Request Builder i tried with just &quot;Poll SCM&quot; project and specified cron job to trigger as &quot;H/2 * * * *&quot;. Upon commits the job is triggered at jenkins. It means that for every commit the jenkins job gets triggered. But Jenkins should trigger the job when PR is created/updated.
I am missing something here certainly which could be basic and new to jenkins pipeline.
Any hint on achieving the desired behavior?
To expand on the answer above - try using:

branch: "origin/pr/${pullRequestId}/from"


Because in groovy, string interpolation is not done for simple strings - i.e. strings within single quotes. See http://groovy-lang.org/syntax.html#_string_interpolation for details on that.