When trying to preview a Mac Catalyst app I run into an issue:
The package product 'NIOTransportServices' requires minimum platform version 10.15 for the macOS platform, but this target supports 10.10 (in target 'NIOTSHTTPServer' from project 'swift-nio-transport-services')
When building a preview the build system seems to not respect the deployment target set.
Obviously, as this is an iOS project with Mac as extra target the MACOSX_DEPLOYMENT_TARGET variable is set to 10.15.
Building and running the app works fine.
Is there a way of manually specifying the deployment target for preview builds?
As it turned out this was a bug in Xcode and is fixed since 12.0.1 and later.