Yarn vs. npm5 determinism

I guess the one thing to take away from this is that js tool authors and c tool authors don't talk to each other enough.

1. The amount of noise in the lock file likely does matter for teams of any modest size

2. Yarn doesn't guarantee determinism for hoisting between different versions, but... in reality there's no reason to expect different behavior simply because there's a version difference.

The second point is pretty key, because it means yarn can deal with the issue through fairly standard means (like versioning, documentation, warnings, etc). Plus, most orgs already handle versioning and compatibility between tools in some form or other.

Finally, NPM 5 doesn't actually guarantee hoisting is deterministic between versions, they just have enough information that they COULD guarantee it. For all we know, NPM 6 will change the format of the file entirely... or perform new hoisting optimizations based on the lockfile that are incompatible with the logic in 5.