All contain-rs crates are now in maintenance-mode


We don’t have enough maintainers for any of our crates, and as such will no longer be accepting meaningful API changes. We will only accept changes to keep things working.

This notably includes:

  • bit-vec
  • bit-set
  • linked-hash-map
  • lru-cache
  • enum-set
  • vec-map
  • linear-map

I started this organization 3 years ago as primarily an annex for collections which were removed from Rust in the 1.0 release blitz. It subsequently grew into a place to develop collections and APIs outside of the stdlib process.

Bringing many collections under a single umbrella was initially a successful project. Every developer that added their collection to the pile gained a network of co-maintainers, while also promising to help maintain the other collections when they could. This was important, because I strongly believe collections require a significant amount of API design and code review, as they push the boundaries of the ownership model, and generally require significant unsafe code.

Near the end of 2015 I became delinquent in my maintenance, as I shifted my focus to completing my Master’s thesis. I then spent a year working at Apple (mostly on Swift), wherein I was contractually barred from even responding to comments on our issue trackers (the Apache license has interesting provisions about official communications).

I can’t really speak for what happened to the others in this time, but ultimately everyone else has basically disappeared. Several feature requests and PRs have sat untouched for well over a year.

I now work on Gecko at Mozilla and can contribute to these projects again, but I simply don’t have the mental bandwidth to maintain these repositories without the others. Especially since working for Mozilla is an actual job, unlike my relatively free-time filled school years. I also just don’t think this is where my time would best be spent anymore (for instance, maintenance of the nomicon is more important to me now).

I am willing to accept new maintainers for these projects, but it will mostly be a “you’re on your own” affair. I probably won’t accept maintainers who I don’t know in some way; these crates have a non-trivial number of users and I’m not going to entrust them to strangers.


Would external reviews help get changes accepted? On a send a PR, review another basis maybe?


Thanks for all you’ve done and are doing for Rust’s collections (and beyond) – and also for the responsible way you’re approaching this!


@Gankro I have some interest in enum-set crate, and would like to take over that project. My GitHub alias is: