Jenkins Mercurial plugin does not detect changes

Question

When my pipeline polls the Mercurial repo for changes it does not detect any change, and new builds are not triggered.

Following the plugin docs, I set up a push hook to trigger the polling, which works fine, but is not able to detect changes. All I get is

Mercurial Polling Log

Started on May 19, 2018 11:58:10 PM

no polling baseline in /var/lib/jenkins/workspace/test-repo on

Done. Took 0 ms

No changes

I am working with: - Jenkins v2.107.3 - Mercurial plugin v2.3

I just created a test mercurial repo with some files with random content to test the setup, and a jenkins pipeline 'polling-test' which checks out the repo and echoes "hello world".

pipeline {
    agent any
    stages {
        stage('Checkout') {
            steps {
                checkout changelog: true,
                    poll: true,
                    scm: [
                        $class: 'MercurialSCM',
                        credentialsId: 'jenkins',
                        revision: 'default',
                        revisionType: 'BRANCH',
                        source: 'ssh://hg-user@hg-server/test-repo'
                    ]
            }
        }
        stage('Tests') {
            steps {
                echo "Hello World"
            }
        }
    }
}

Also the Poll SCM option is checked out, and without any schedule.

I modify the repo doing something like:

$ echo "foo" > bar
$ hg add bar
$ hg commit -m "change"
$ hg push

And then the polling is triggered with

$ curl "https://jenkins-server/mercurial/notifyCommit?url=ssh://hg-user@hg-server/test-repo"
Scheduled polling of polling-test

The polling log shows it has triggered, but found no changes.

What am I doing wrong? How can changes be detected?

Answer 1

I was able to make the polling work properly by adding a Mercurial installation in the "global tools", changing the pipeline script to

pipeline {
    agent any
    stages {
        stage('Checkout') {
            steps {
                checkout([$class: 'MercurialSCM', credentialsId: 'jenkins', installation: 'Mercurial', source: 'ssh://hg-user@hg-server/test-repo'])
            }
        }
        stage('Tests') {
            steps {
                echo "Hello World"
            }
        }
    }
}

while keeping the Polling option checked, and of course running the pipeline a first time manually to get a reference changeset.