Jenkins Multibranch Pipeline Lacks Support for PathRestriction triggers

Question

Goal

Build our repo more frequently for java changes and less frequently for docker base image changes.

Situation

We have two multibranch pipeline jobs: build-java and build-base-docker . We want the build-base-docker to trigger for master & feature branches only when pushes contain changes beneath /docker .

Approach

Following cloudbees How to Customize Checkout for Pipleine Multibranch? doc we implemented the changes below.

However, a changes to src/main/java/foo.java triggers the build-base-docker job for that branch when we'd don't want it to do so.

Is this really just JENKINS-36195 bug or am I doing something wrong which results in the unexpected trigger?

node('java-build') {

stage ('git checkout') {
    checkout([
            $class: 'GitSCM',
            branches: scm.branches,
            extensions: scm.extensions + [
                [$class: 'PathRestriction', excludedRegions: '.*', includedRegions: 'docker/.*']
            ],
            userRemoteConfigs: [[credentialsId: 'our-git-repo-deploy-key', url: 'git@github.com:we/our-repo.git']]

    ])
}
...
}

Answer 1

If Jenkins can't handle path restrictions on a multibranch pipelines well, then we do it from our pipeline code (or from a shared library to reduce duplication).

If we have multiple checkouts, this can get a little problematic as all will be reported. However, provided they don't use the same layout, the risk of false positives is low. Eg, the jenkins-shared-library usually sees changes beneath /vars dir not docker.

node() {
    if ( ! doChangesRequireBuild('^docker/.*')) {
        currentBuild.result = 'ABORTED'
        return 'Changes not made to docker/... base image files. Aborting build'
    }
}

/**
 * Provide List of changed file paths since last successful build
 */
def getChangedFiles() {
    def found = []

    for (def changeSet in currentBuild.getChangeSets()) {
        for (def change in changeSet.logs) {
            for (def path in change.paths) {
                found.add(path.path)
            }
        }
    }
    return found
}

/**
 * do changes since last successful build mandate a build?
 * @param pathRegex path restriction regex pattern
 * @return true if any file paths match the regex
 */
boolean doChangesRequireBuild(def pathRegex) {

    for (def path in getChangedFiles()) {
        if ( path ==~ pathRegex) {
            return true
        }
    }
    return false
}