Scaling the Hare community August 28, 2023 by Drew DeVault

I started the Hare project on December 27th, 2019, with a small commit introducing a lexer and a yacc parser for prototyping the grammar. In the nearly four years since then, a community of over one hundred contributors has grown around the project, including some eight co-maintainers working together to incorporate dozens of patches every week.

Over the past several weeks, I have been working with the other maintainers and project leaders to discuss possible reforms to the community structure and workflow to reduce bottlenecks and streamline the work, to reduce frustration with slow patch approval and make it easier for people to work autonomously — and to reduce the, uh, “Drew bottleneck”.

As Hare is organized with a mailing-list-based workflow for preparing, reviewing, and applying patches, we have drawn inspiration from how the largest mail-based project — Linux — scaled up to its massive size. I’m fond of the Linux model because it is both effective and simple, so it can be applied to a medium-size project and scale all the way up to the largest free software project in the world.

To this end, the changes are focused on:

The reforms have been under development since April and should be completed in the next few weeks, then tested and refined over time. Let’s sum up each of the efforts to achieve this.


We have introduced a MAINTAINERS file to the Hare repository, as well as a maintainer policy which outlines the rights, responsibilities, and procedures that these maintainers employ. This file is adapted from a similar approach in Linux and allows us to formally dole out responsibilities over subsystems in the codebase. The areas of responsibility include things like “AArch64 support” (maintained by Willow Barraco), “Date/time support” (Byron Torres), and so on, as well as a top-level list of global maintainers: myself, Ember Sawady, Sebastian, and Bor Grošelj Simić.

We have also standardized the way that maintainers work on their patch queues so that we can communicate to each other more effectively the status of ongoing code reviews and patch approvals.

These changes:

  1. Empower notable contributors to oversee their subsystems
  2. More clearly assign code review responsibilities across subsystems
  3. Reduce the Drew bottleneck

Each maintainer has push access and can review, approve, and apply patches independently.

Distributing and autonomizing Hare development

Hare maintains centralized resources for governing the upstream project, including our primary mailing lists, bug trackers, and source code repositories. However, larger initiatives within the project can often benefit from access to dedicated infrastructure, allowing them to organize independently without being bottlenecked by the constraints of upstream.

Today, there is already a significant degree of autonomous work being done on Hare, but it’s organized informally and has some accessibility problems. Many Hare maintainers have their own personal Hare trees and organize large efforts (like the module3 work or linear types research) alone, perhaps looping in one or two other contributors on an informal basis to participate in this work. We like this approach but want to encourage it to happen with improved organization, communication, and efficiency.

We want to encourage participants to self-organize independently of upstream. To keep these efforts well-organized and accessible, we have established a TREES file to keep track of trees maintained independently of upstream. This includes for now a list of maintainer’s personal trees, where they stage work on their various subsystems, to make these efforts more visible to the community. It will be expanded in the future in two directions: permanent and project trees.

A permanent tree is a tree maintained in the long-term for a specific purpose, for instance the maintenance of a platform port. For example, Willow, the aarch64 maintainer, might establish a permanent hare-arm tree to organize work associated with ARM ports. This could include an ARM-specific bug tracker and mailing lists, as well as a source tree. Other candidates include cryptography, date/time, and other long-term, large-scale efforts within the Hare community, where work is conducted independently and regularly sent to Hare upstream in batches.

This is analogous to the Linux model, where something like hare-arm corresponds to linux-arm, and other examples of permanent trees include linux-drm, linux-btrfs, and so on.

Project trees have a medium-term lifecycle, and are started to organize work around a specific initiative in the Hare project. Two efforts which have been ongoing under this framework in an informal model include the module3 rewrite and research into linear types. These larger, research-heavy projects can benefit from more organized collaborative resources and visibility, to be dismantled once merged upstream.

Establishing an RFC process

Changes to the language are implemented through a process of community consensus. The unclear nature of the consensus process and issues with communication tools throughout the community has occasionally led to cases where the status of that consensus was unclear, leading contributors to expend work on projects which, when presented for broader consensus, require frustrating retooling and rewrites to be accepted.

We are establishing an RFC process to address these issues. The RFC process is designed to be a tool rather than a bottleneck. It is not required for all changes. The author of a change can opt-in to the RFC process, for changes of any size, if they believe that a structured conversation around the proposed change would be useful to their work. A reviewer or maintainer can also request that the RFC process is invoked for a change if they believe it would be useful. Some guidelines for determining the requirements for a change to be discussed as an RFC have been prepared, but it will ultimately be left to the discretion of the participants.

Changes to be discussed within the RFC framework will follow the process outlined in the RFC process document, wherein proposals are prepared and submitted to the new hare-rfc mailing list for discussion.

Defining the BDFL role

One of the problems we’re working on fixing is my status as the “Drew bottleneck”. Work to decentralize development and establish more maintainers goes a long way towards addressing this, but it’s also helpful to figure out exactly what my role as a BDFL (Benevolent Dictator for Life) actually means for the project.

I have written a personal note to the repository in docs/ which elaborates on these topics. I view the role of BDFL as a service to the community, rather than something that is imposed on the project, and I possess unique tools in this role that the community can call upon when necessary. This includes matters such as overseeing fiduciary responsibilities, setting the long-term vision and planning for the project, and assigning rights and responsibilities to other participants.

This document also clarifies how best to make use of my resources such that they can be leveraged efficiently when needed without introducing too many bottlenecks, such as good ways to draw my attention to specific issues that require BDFL feedback or manage administrative tasks like updating DNS records and ACLs on SourceHut.

Social spaces and the code of conduct

Hare worked without a code of conduct for a long time; even when working alone and at my discretion as the sole moderator I am generally competent at keeping jerks out of the community and making people feel welcome. However, as the community grows, moderation is a burden which is more efficient when shared with the rest of the team. The community shapes its own culture, and empowering participants to steer the discussions and assist in moderation is an important part of placing the culture in the hands of the community.

For these reasons, and to more clearly signal our values and expectations to new community members, we introduced a Code of Conduct and a committee of three trusted community members to oversee conflict resolution:

We are also expanding the role of community spaces to include some social space in addition to working space. One of the foundational values of the Hare community is professionalism: the working spaces are kept on-topic and professional in tone, though they don’t enforce any kind of overt formality. However, the community is also a fun place to be and many friendships have formed here — that’s something to be encouraged!

We noticed a few groups of Hare contributors forming friendships and taking their social activities outside of the Hare spaces — respecting the on-topic rules and professional attitude of these spaces. But, if you get a group of excited Hare contributors in a room they’re eventually going to talk about Hare, and this started leading to cases where a few Hare contributors would talk outside of the Hare community about their ideas, form a consensus in their insular group, then get put out when this consensus does not translate to the broader community.

To improve matters, we have established the #hare-soc IRC channel as a lighter social space for the Hare community on the Libera Chat IRC network, where we hope that these friendships and connections can be encouraged, fun is allowed, and we can keep the community communicating better together without affecting the professional and on-topic attitude of the working spaces. The expanded role of moderators and the new code of conduct is anticipated to provide the necessary tools to maintain a more social space in the Hare community where the standards can be loosened while maintaining a respectful and inclusive environment.