jenkins git plugin: git environment variables are ignored in the checkout step

Question

It's seems impossible to pass environment to the git binary when using the jenkins checkout step https://www.jenkins.io/doc/pipeline/steps/params/scmgit/

This is necessary so I add enable tracing with git (e.g. using the GIT_CURL_VERBOSE environment variable https://git-scm.com/book/en/v2/Git-Internals-Environment-Variables)

Here's my example pipeline to reproduce the problem:

pipeline {
    agent any
    environment {
        GIT_CURL_VERBOSE = true
    }
    stages {
        stage('Build') {
            steps {
                sh '''rm -rf git-dir
                '''
                dir('git-dir') {
                   checkout scmGit(branches: [[name: '*/master']], extensions: [], userRemoteConfigs: [[url: 'https://github.com/jenkinsci/git-plugin.git']])
                }
                sh '''printenv
                    ls -al
                '''
            }
        }
    }
}

In the clone using the checkout step, GIT_CURL_VERBOSE is ignored and nothing is printed. In the printenv output I see the environment is set though.

Is this a bug in the jenkins git plugin? Can I enable tracing anyway?

Answer 1

It seems you ran into this bug: https://issues.jenkins.io/browse/JENKINS-68580

You could invoke git directly as a workaround, if you replace the checkout step with this:

dir('git-dir') {
  sh '''rm -rf .git
  git init 
  git fetch --no-tags --force --progress -- https://github.com/jenkinsci/git-plugin.git +refs/heads/*:refs/remotes/origin/*
  '''
}

Tracing output will be available.