title: 'Allow duplicates to be skipped' warning and 409 error for NuGet push on Azure DevOps Server
body: <p>In Azure DevOps Server (version 2019.0.1) running on a Windows Server 2019 agent, with the 'Allow duplicates to be skipped' option selected for NuGet push task, a warning is displayed:</p>
  
  <blockquote>
    <p>The 'Allow duplicates to be skipped' option is currently only available on Azure Pipelines. If NuGet.exe encounters a conflict, the task will fail.</p>
  </blockquote>
  
  <p>The task results in the following error that causes the task to fail indicating that the above warning applies:</p>
  
  <blockquote>
    <p>Response status code does not indicate success: 409 (Conflict - The feed already contains 'MyPackage X.Y.Z'. (DevOps Activity ID: 1A57312F-3C56-4E4D-9E78-73C7072A288F)).</p>
  </blockquote>
  
  <p>I'm wondering if this issue is particular to Azure DevOps Server (rather than Azure DevOps Services), or if I'm doing something wrong, or if there is another workaround. I noticed someone else has the same issue from <a href="https://stackoverflow.com/questions/46115212/ignore-duplicates-when-pushing-nuget-package-to-nuget-org-from-vsts/46151147#comment95472072_46151147">this comment</a> on another question where it was mentioned that the option was available after someone asked how to ignore error 409 (duplicate package).</p>
  
  <p>I would like to ignore duplicate packages using the NuGet task and ideally the 'Allow duplicates to be skipped' option on Azure DevOps Server. I'm aware that it could be resolved using scripting, but I'd prefer to avoid that if possible. Any help appreciated.</p>