### Problem to solve When using the GitLab Package Registry to publish NuGet packages, a duplicate package name/version can be uploaded. This may be great for snapshots, but you may want your `releases` to be immutable. ### Proposal Add a setting that will allow you to define (at the group level) whether or not duplicate NuGet packages are allowed. ### Further details Please make sure that the dotnet cli command line option "--skip-duplicate" works, which means you should return the same error that nuget.org returns, when a duplicate is uploaded. - dotnet nuget push documentation: https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-nuget-push - As per https://gitlab.com/gitlab-org/gitlab/-/issues/262081#note_587195702, we'll also need to consider behavior for symbol packages which by default allow duplicates. - As per https://gitlab.com/gitlab-org/gitlab/-/issues/336225#note_633958497 we will consider adding a setting to overwrite existing packages