title: How to reference an Azure DevOps matrix variable, inside an expression?
body: <p>I'm trying to figure out how to access an Azure DevOps matrix variable, in a compile time expression. The reference value is always null/empty/missing. Like the variable hasn't been set.</p>
  
  <p>here's a sample yml file I was trying:</p>
  
  <pre><code>
  jobs:
  - job: LinuxBuild
    displayName: Pew Pew
    strategy:
      matrix:
        debugJob:
          buildConfiguration: Debug
        releaseJob:
          buildConfiguration: Release
    pool:
      vmImage: 'ubuntu-16.04'
  
   steps:
    - script: echo ${{variables.debugJob.buildConfiguration}} ## &lt;-- always null/empty
  
    - script: echo ${{variables['debugJob.buildConfiguration']}}  ## &lt;-- always null/empty
  
    - ${{ if eq(variables.debugJob.buildConfiguration, 'Debug') }}: ## &lt;-- never ran/executed
      - template: doSomething.yml@templates
  </code></pre>