When we initially moved crates into the rust-lang organization from the rust repository we ended up with some duplication. For example the in-tree libterm is in theory the same as rust-lang/term, except that rust-lang/term has drifted over time to be different than libterm in-tree. This drift is problematic, however, and can cause confusion. Additionally, it’s somewhat odd having the same code in two different locations.
Now that Rust and the standard library is stable, there should in theory be 0 breaking changes sweeping through the compiler to update old code. This is why we have avoided submodules in the past as landing changes in the submodule, then landing the submodule update, is a difficult process. With a stable release, however, the submodules should be guaranteed to compile until the end of time, perhaps with some minor elaboration along the way.
I would like to propose that we start using submodules for the following crates:
- serialize (rustc-serialize)
- log - also add env_logger
- libc - new apis are added here somewhat regularly, but they are rarely used in the compiler and standard library. The standard library has its own area for defining new APIs.
Other candidates are the following, along with reasons to not pursue them at this time:
- flate - this crate is not in rust-lang, and the “replacement” of flate2 also has a dependency on miniz_sys, and it’s a little bit overkill to be including these two for something so minor
- rand - this dependency is underneath the standard library, and the crate in rust-lang/rand is not configured to have such placement (it depends on the standard library)
Having this infrastructure and precedent will allow us to perhaps easily add in new dependencies in the future, such as pulldown-cmark (a markdown parser written in Rust). All submodules would be required to use stable Rust (and probably have no dependencies of their own for the time being).
What do others think about this strategy? Perhaps it’s not worth it?