How to add condition to a stage in azure-pipeline.yaml properly

I have a pipeline that creates a chocolatey package based on the repo.

• In the first stage I create the package, check if the package created and copy the nupkg to the destination. That works perfectly as it is.
• In the second stage I'd like to run a Vagrant test that tests the choco package but only when the file created. So based on the previous file exist check i'd add the condition to the whole stage.

In the first stage the condition on the CopyFiles works just perfectly, but when I add the same condition on the 2nd stage it just skips every single time. Without the condition it starts and writes the "test".

So far the azure-pipeline.yaml's interesting part is the following. The "*****" is mostly for anonimity.

variables:
  solution: *****'
  buildConfiguration: 'Release'
  buildPlatform: 'Any CPU'
  chocoSource: '*****'
  localChocoFolder: '.\chocolateypack'
  binaryInputFolder: *****'
  localFolder: '$(Build.SourcesDirectory)\Package'
  dropFolder: *****'
  vagrantDropFolder: *****'
  fileExists: true
  
stages:
- stage: BuildCommands
  displayName: Build Commands stage
  jobs: 
  - job: BuildCommands
    timeoutInMinutes: 120
    displayName: Build commands job 
    pool:
     name: 'Bugzing'

    *****
    *****
    *****
    *****
    *****

    - task: PowerShell@2
      displayName: 'Check for existing files in target folder'
      inputs:
        targetType: 'inline'
        script: |         
          # Access pipeline variables
          $localFolder = "${env:localFolder}"
          $dropFolder = "${env:dropFolder}"

          # Get the list of local files
          $localFiles = Get-ChildItem -Path $localFolder -Recurse -File

          foreach ($localFile in $localFiles) {
            $relativePath = $localFile.FullName.Substring($localFolder.Length)
            $targetFilePath = Join-Path $dropFolder $relativePath

            if (Test-Path $targetFilePath) {
              Write-Host "##vso[task.logissue type=warning]File already exists in target folder: $targetFilePath"
              Write-Host "##vso[task.complete result=SucceededWithIssues;]"
              exit 0
            }
          }
          
          Write-Host "##vso[task.setvariable variable=fileExists]false"

    - task: CopyFiles@2
      condition: and (succeeded(), eq(variables['fileExists'], 'false'))
      displayName: 'Copy installer'
      inputs:
        SourceFolder: '$(localFolder)'
        Contents: '**'
        TargetFolder: '$(dropFolder)'
       
- stage: VagrantTest
  displayName: Test Package With Vagrant
  dependsOn: BuildCommands
  condition: and(succeeded(), eq(dependencies.BuildCommands.outputs['BuildCommands.fileExists'], 'false'))
  jobs: 
  - job: BuildCommands
    timeoutInMinutes: 120
    displayName: Build commands job 
    pool:
     name: 'Bugzing'
     
    steps:
    - task: PowerShell@2
      displayName: stage 2 echo test
      inputs:
        targetType: 'inline'
        script: |
          echo "test"

To make your pipeline work as expected, you need to adjust the followings.

1. If you want to use an output variable in future stages, add the isoutput property to your variable and set the value to true.

   Write-Host "##vso[task.setvariable variable=fileExists;isOutput=true]false"

2. When you set a variable with the isoutput property, you can reference that variable in later stages with the task name and the stageDependencies syntax.

• Add a name to your PowerShell@2 task where you create the output variable fileExists in stage BuildCommands as shown below.

    - task: PowerShell@2
      name: setVar

• Once isoutput=true is added to your output variable, the syntax changes for referencing an output variable in the same job. Change the condition of your CopyFiles@2 task to:

  condition: and (succeeded(), eq(variables['setVar.fileExists'], 'false'))

• Change the condition of your VagrantTest stage to

  condition: and(succeeded(), eq(dependencies.BuildCommands.outputs['BuildCommands.setVar.fileExists'], 'false')).

You can refer to the following example:

stages:
- stage: BuildCommands
  displayName: Build Commands stage
  jobs: 
  - job: BuildCommands
    timeoutInMinutes: 120
    displayName: Build commands job 
    steps:
    - task: PowerShell@2
      name: setVar
      displayName: 'Check for existing files in target folder'
      inputs:
        targetType: 'inline'
        script: |         
          Write-Host "##vso[task.setvariable variable=fileExists;isOutput=true]false"
    - task: CopyFiles@2
      condition: and (succeeded(), eq(variables['setVar.fileExists'], 'false'))
      displayName: 'Copy installer'
      inputs:
        SourceFolder: '$(localFolder)'
        Contents: '**'
        TargetFolder: '$(dropFolder)'
       
- stage: VagrantTest
  displayName: Test Package With Vagrant
  dependsOn: BuildCommands
  condition: and(succeeded(), eq(dependencies.BuildCommands.outputs['BuildCommands.setVar.fileExists'], 'false'))
  jobs: 
  - job: BuildCommands
    timeoutInMinutes: 120
    displayName: Build commands job 
    steps:
    - task: PowerShell@2
      displayName: stage 2 echo test
      inputs:
        targetType: 'inline'
        script: |
          echo "test"

Result:

See the detailed info about output variable from Set an output variable for use in future stages.