在我们的一个Jenkins作业中，签入到拉取请求中，我们依赖于Bitbucket的实现细节，即拉取请求合并提交，可以使用pull-requests/*/merge访问它。
Bitbucket已删除对3路合并的支持，因此我们无法运行：

if (isPR(config.BRANCH)) {
            echo 'In PR type commit'
            PR_ID=parsePRId(config.BRANCH)
            TARGET_COMMIT="pull-requests/$PR_ID/merge"
            FROM_COMMIT="pull-requests/$PR_ID/from"
        } else {
            echo 'Non PR type commit'
            TARGET_COMMIT=config.BRANCH
            FROM_COMMIT=config.BRANCH
        }

        // Fetch hash of from commit for marking build status
        sh "git fetch origin $FROM_COMMIT"
        result.branch = config.BRANCH
        result.fromCommitId = sh(returnStdout: true, script: "git rev-parse FETCH_HEAD").trim()
        result.fromCommitIdShort = sh(returnStdout: true, script: "git rev-parse --short FETCH_HEAD").trim()

        try {
            // Checkout target commit
            sh """
                git fetch origin $TARGET_COMMIT && \
                git checkout -f FETCH_HEAD
            """
            result.targetCommitId = sh(returnStdout: true, script: "git rev-parse FETCH_HEAD").trim();
            result.targetCommitIdShort = sh(returnStdout: true, script: "git rev-parse --short FETCH_HEAD").trim();
        } catch (Exception err) {
            result.targetCommitId = null
            result.targetCommitIdShort = null
        }

最终目标是 checkout pull请求，以便在monorepo中构建/部署微服务。