title: Why is Azure Pipelines Docker task buildContext empty?
body: <p>I'm running a pipeline and cannot figure out why the buildContext in the Docker task is empty even though the cmd script clearly shows that the directory is not?</p>
  
  <p>The tasks in my <code>azure-pipelines.yml</code> are as follows:</p>
  
  <pre><code>- task: CmdLine@2
    inputs:
      workingDirectory: './services/UI.Web'
      script: 'dir'
  
  - task: Docker@2
    inputs:
      command: 'buildAndPush'
      containerRegistry: 'docker'
      repository: 'username/repository'
      Tags: tag
      Dockerfile: './services/UI.Web/Dockerfile'
      buildContext: './services/UI.Web'
  </code></pre>
  
  <p>The output in the pipeline logs are as follows:</p>
  
  <pre><code>Directory of D:\a\1\s\services\UI.Web
  
  ... list of files and folders ...
  
  10 File(s) 18 Dir(s) 179,798 bytes
  </code></pre>
  
  <p>and</p>
  
  <pre><code>"C:\Program Files\Docker\docker.exe" build -f D:\a\1\s\services\UI.Web\Dockerfile -t username/repository:tag D:\a\1\s\services\UI.Web
  Sending build context to Docker daemon  3.072kB
  </code></pre>
  
  <p>If I change the <code>buildContext</code> to <code>'./services'</code> then the log output changes to</p>
  
  <pre><code>"C:\Program Files\Docker\docker.exe" build -f d:\a\1\s\services\UI.Web\Dockerfile -t username/repository:tag d:\a\1\s\services
  Sending build context to Docker daemon  2.701GB
  </code></pre>