Building just SPM dependencies to cache in a Docker layer

[SDGGiesbrecht (Jeremy David Giesbrecht)]

Incremental builds with Swift Package Manager and Linux / Docker

I'm using Swift Package Manager to build my Swift server app in a Linux Docker container. Each time I rebuild it fetches all of the dependencies and rebuilds them all. Recently I started using Swift-NIO as a dependency and it takes a while to compile. Are incremental builds supported on Linux? I tried to get incremental builds working by having my Package.swift + some dummy files copied into docker -> build -> copy in the real source files -> build. I was hoping the dependencies of the first bu…