Packages registry allows pushing same version nuget packages

Summary

It is possible to push identical nuget files into a registry multiple times.
The package is not overwritten, but each file stored in the registry.
The -SkipDuplicate option for nuget push has no influence on this bahaviour.

Steps to reproduce

• have a project with some nupkg in a directory
• have a .gitlab-ci.yml like this:

stages:
    - push

push nuget:
    stage: push
    image: mcr.microsoft.com/dotnet/framework/sdk:4.8
    script:
       
       - nuget source Add -Name gitlab -Source <repo-api> -UserName <uname> -Password <pass>
       - $files = Get-ChildItem ".\packages\" -Recurse -File -Name
       - for ($num = 0; $num -lt $files.Count; $num++) 
         {
           $name = $files[$num];
           $name = "packages\$name";
           echo "file $name";
           nuget push $name -Source gitlab -NonInteractive -SkipDuplicate 
         }

• run pipeline multiple times

What is the current bug behavior?

• Files are pushed even if already existing.
  • this results in multiple of the same file added to the registry
• nuget push -SkipDuplicate does not prevent this

What is the expected correct behavior?

• pushing a package that already exists should return a 409 error code

• -SkipDuplicate should .. skip duplicates

Versions

Gitlab: Self-hosted CE 14.0.5
Runner: V:14.0.1 Rev:c1edb478

~bug