rust-lang/cargo — pull request #618 by alexcrichton (2014-09-22 01:01:26+00:00)
Title: Implement package id specifications

This gives cargo a way to uniquely reference a package within a dependency graph. This is currently only used for `cargo update` and `cargo pkgid`, but this will extend in the future to possible configuration keys in the manifest, other commands like `clean`, etc.

Closes #593