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Retooling the Rust Libs Team team for 2018

The Libs Team met today to discuss a weighty topic: what is its mission as a team, and are we set up to achieve it?

As team lead, I took the liberty of proposing a mission statement:

To improve the quality of the crate ecosystem, as a product.

Working backwards:

  • “as a product” means that we need to focus on the end-to-end experience people have with the ecosystem. It’s not enough to have great libraries if no one can find them. It can be a problem to have too many libraries. Docs count for a lot!

  • “the crate ecosystem” means that the Libs Team needs to look far beyond std and help look after the library ecosystem as a whole. The Libz Blitz was one of our first major attempts on this front.

  • “improve the quality” means that we don’t own or oversee the ecosystem, but that we work together with library authors to improve the experience. What quality means, and what aspects to prioritize, is of course also important to nail down.

That’s a lofty goal! Let’s take a look at how we’ve approached it in the past, and then talk about the future.

Please comment on the internals post!

The Libs Team circa 2017

Last year, the Libs Team split its focus onto two main topics:

For std, the work involved shepherding and deciding on RFCs and jointly reviewing PRs that impact the stable API surface. Despite the fact that std is not substantially growing, the workload here is sizable!

For the Blitz, the work involved leading crate evaluations, doing API walks in synchronous meetings, and working with crate authors to help push through changes. As by-products, the team also worked on the API guidelines and, to a lesser extent, the Cookbook.

These efforts definitely made a positive impact on our goals, but collectively the team feels that there’s more we could be doing, and that a rebalancing of priorities is in order–partly drawing on lessons from our 2017 work.

Retooling the team in 2018


One clear lesson from the Libz Blitz and the impl Period is that there are a lot of people out there who are excited to help improve Rust’s ecosystem, but we lack the infrastructure and leadership bandwidth to direct this energy effectively.

So the Libs Team needs to grow its leadership, and grow to accommodate people eager to pitch in. Today we announced two additions to the team, which is a good step.

However, a limiting factor is the current “monolithic” structure to the team, which means that every member is expected to participate in all activities, including signing off on std changes. To remove this bottleneck, we are considering a “working group” model, in which team members cluster into smaller working groups that tackle particular topics, where each member participates only in the groups they have time/interest for. Examples groups might be: std, SIMD, networking, API guidelines, cookbook. To some degree these groups exist informally now, but we want to be more systematic about them, explicitly delegating decision-making power and designating a lead for each group.

The working group model should allow us to drastically increase the number of people involved in the team, while at the same time making us more agile by moving day-to-day decision-making to smaller, more focused groups.

We’re working with the Core Team to flesh out these ideas, in part because several other subteams are pursuing similar thoughts; expect an RFC on this topic soon!

Areas of focus

With the above changes, the Libs Team should be able to devote much more of its focus to the broader crates ecosystem, and not just std. But where should that focus go?

What follows are some preliminary thoughts, with the main goal of stirring up discussion.

Let’s go back to the question of “product quality” for the ecosystem. I’d break that down as follows:

  • Crate availability. Does there exist a crate for your needs?
  • Crate discoverability. Can you find that crate?
  • Crate quality. Is the crate good? How can you tell?
  • Crate interoperability. Does the crate fit well into the rest of the ecosystem?

Last year, the Libs Team’s focus was clearly crate quality. Now we want to retool to hit on all of these topics.


Where are the gaps in the ecosystem? That’s not just missing crates, but crates that are missing important features in their domain. In the past, the Libs Team has sometimes tried to look at availability issues by examining the entire ecosystem and comparing to ecosystems for other languages–an approach that’s never panned out.

I think instead we should spin up working groups devoted to particular topics/goals. For example, we could have a SIMD working group with the mandate to produce a stable SIMD API and the power to make decisions on related RFCs. But working groups could also be more broad, e.g. by bringing together people interested in “networking” in general. The theory is that these domain experts, by talking more regularly, can come to better understand the gaps and turn them into contribution opportunities. They can also, of course, work to improve the quality of the crates in their domain.

It’s important to note, though, that working groups should be spun up only when we have committed leaderhip for keeping up momentum and organization of the group. That comes back to team growth.


In the “distant” past (circa 2016), we floated ideas like the Rust Platform, that involved “blessing” crates and tools that would then, in some sense, be “shipped” as part of the Rust distribution. Part of the goal was to improve discoverability by officially curating these crates. But in discussion with the broader community, it became clear that this approach just has too many downsides; it takes the oxygen out of the room for crate iteration and competition, amongst other things.

Instead, in 2017, the crates.io team put a lot of work into improving discoverability within crates.io. The Libs Team also intended to turn the Cookbook into a central point of discoverability, but that work hasn’t fully panned out.

I don’t think the work here is finished. As I said in my #Rust 2018 post, I think this year we should focus on shipping a new iteration of Rust as a product, and that should include a more polished discoverability story. As such, I think we should have a working group dedicated purely to improving the process of finding and evaluating crates. (There are lots of specific ideas about further improvements, but those are out of scope for this post.)


The Libs Team put a lot of its focus in 2017 on crate quality. As KodrAus put it, this happened both strategically and tactically:

  • Strategically: by creating resources like the API guidelines, we started to give library authors much more guidance how to create a high quality crate.

  • Tactically: through the Libz Blitz, we directly impacted the quality of specific crates.

Both of these efforts were shaped by the Libz Blitz, which purposefully targeted nearly-stable crates in an attempt to help clear up remaining design questions and polish toward a 1.0.

These kinds of quality improvements are one of the highest-leverage activities the Libs Team can take on, so we want to expand our efforts here. Some ideas and open questions include:

  • Supplementing the API guidelines with more “long form” material, e.g. by writing detailed “design evaluation” documents that explain all the design choices made in a particular crate.

  • Surfacing pockets of the ecosystem that lack uniformity, such as the current situation around -sys crates, and working to produce a set of consensus conventions.

  • Improving maintenance of vital crates (e.g. libc, rand, cc) by bringing on more contributors.

  • Doing deeper dives into particular domains that need more design work; dhardy took on such work with the rand crate, and there are several other areas that need more than a Blitz-style treatment to get to 1.0-level libraries.

I’m sure there are other avenues to explore, and I’d love to hear your ideas! It’ll also take some work to figure out how to map these to working groups we can plausibly staff.


One important aspect of looking at the ecosystem as a whole is making sure that crates work well together. For example, there’s currently an issue with error-chain that is preventing smooth interop with failure. The Libs Team should be working to surface and help solve this kind of issue. Probably this is best done by working toward another useful goal: building and documenting mid-sized sample applications that plug together various Rust libraries.

Cross-cutting concerns

Finally, a general point: to fully achieve its mission, the Libs Team needs to have much more contact with the ecosystem in general; the team should understand what libraries are becoming important in which areas, and spend time checking them out and helping contribute. There are a lot of ways we could do that, but most fundamentally this means bringing more folks working in particular sub-ecosystems into the Libs Team working groups. Thoughts on how we might structure such an effort are welcome, particularly from crate authors!

Wrapping up

This post was essentially a brain-dump of my current thinking about how to take the Libs Team to the next level. I’m eager to hear from you about the problems you see with the ecosystem, the ways you can envision the Libs Team helping, and best of all, the ways you’d like to be involved.