Jenkins pipeline determine if a branch is for Bitbucket pull request

Question

I'm using Jenkins together with the Bitbucket branch source plugin.

Everything works great, but I want to be able to run/exclude certain stages in my pipeline depending on whether the branch is associated with a pull request or not, such as:

pipeline {
  stages {
    stage('build') {
      //compile
    }    
    stage('package') {
      when {
        environment name: 'IS_PULL_REQUEST', value: 'true'
      }      
      //create deployable package
    }
  }
}

Jenkins knows when the branch is for a PR because it merges the source with the target and also displays the branch in the pull request folder on the multibranch pipeline page.

Is there an environment variable I can use within the pipeline to exclude/include stages?

Answer 1

You can use BRANCH_NAME and CHANGE_ID environment variables to detect pull requests. When you run a multibranch pipeline build from a branch (before creating a pull request), the following environment variables are set:

• env.BRANCH_NAME is set to the repository branch name (e.g. develop),
• env.CHANGE_BRANCH is null,
• env.CHANGE_ID is null.

But once you create a pull request, then:

• env.BRANCH_NAME is set to the PR-\d+ name (e.g. PR-11),
• env.CHANGE_BRANCH is set to the real branch name (e.g. develop),
• env.CHANGE_ID is set to the pull request ID (e.g. 11).

I use the following when condition in my pipelines to detect pull requests:

when {
    expression {
        // True for pull requests, false otherwise.
        env.CHANGE_ID && env.BRANCH_NAME.startsWith("PR-")
    }
}