Comment by MetaCosm

> In short, original developer has the clone of the OpenGL library in their 'src' directory. While working on Haunts his making changes to it and not pulling updates from upstream. All is well, things will always build on his machine because as you say, it won't update unless he does 'go get -u'.

The important addition is -- he does not check this clone into his OWN source control, so his source control doesn't have a complete hermetic version of the application, it has a "partial" application... or really "application bits".

> Fast forward to when the community takes over, they clone the Haunts project and attempt to build it. Now they are using the HEAD of the 'github.com/go-gl/opengl/gl' repository, as specified by the imports path and they find that it no longer compiles.

If he had checked it into his version control system (you might call it forking, I call it localizing), they would have had the EXACT same version as him and they would not have had to fulfill that dependency on their own. Also, the same import path would continue to work off this local checked in version.

> By forking, or maintaining your own copy of library, you get a level of isolation from the upstream developers.

I thought that maintaining your own local copy of libraries under /src was the norm for go developers, as the value of hermetic checkouts goes hand in hand with some other Go'isms like static built binaries.