How to run stages with and without matrix in parallel in Jenkins declarative-pipeline?

Question

I am trying to run non-matrix stage with matrix stage in parallel. I want stage ('Build - Win Mac') & stage ('Build - Linux') to run parallel. As per https://www.jenkins.io/doc/book/pipeline/syntax/#declarative-matrix "It is not possible to nest a parallel or matrix block within a stage directive if that stage directive is nested within a parallel or matrix block itself". So I am looking for a workaround for this situation. Please find below my sample stages and suggest how i can achieve this

stages {
    stage ('Build') {
        stage ('Build - Win Mac') {
          // non-docker build for Win & Mac using Matrix
          matrix {
                axes {
                    axis {
                        name 'PLATFORM'
                        values 'Win', 'Mac'
                    }
                    axis {
                        name 'ADDRESS_SANITIZER'
                        values 'disabled', 'enabled'
                    }
                }
            stage ('build'){
                steps {
                    // build step for win, mac
                }
            }
       }
       stage ('Build - Linux'){
       // docker build for Linux
       }
    }
}

Answer 1

I can't make it with a pure declarative pipeline but If you mix declarative + scripted it can be possible

pipeline {
    agent any;
    stages {
        stage('parallel') {
            parallel {
                stage('metrix-build') {
                    steps {
                        echo "Metric-Build"
                        // will take care Metrix kind of scenario with scripted way [start]
                        script {
                            def axisNode = ["osx-agent-1","osx-agent-2"]
                            def axisTool = ["jdk7","jdk8"]
                            def tasks = [:]
                            
                            for(int i=0; i< axisNode.size(); i++) {
                                def axisNodeValue = axisNode[i]
                                for(int j=0; j< axisTool.size(); j++) {
                                    def axisToolValue = axisTool[j]
                                    tasks["${axisNodeValue}/${axisToolValue}"] = {
                                        node(axisNodeValue) {
                                            def javaHome = tool axisToolValue
                                            println "Node=${env.NODE_NAME}"
                                            println "Java=${javaHome}"
                                        }
                                    }
                                }
                            }
                            parallel tasks
                        } 
                        //[End here]
                        
                    }
                }
                stage('non-metric-build') {
                    steps {
                        echo "non metrics build"
                    }
                }
            }
        }
    }
}