oRFC: 1 The Collective Code Construction Contract (C4)¶
The Collective Code Construction Contract (C4) is an evolution of the github.com Fork + Pull Model, aimed at providing an optimal collaboration model for free software projects. This is revision 1 of the C4 specification.
Name | C4.1 |
Editor | Jeremy Rossi <jeremy at jeremyrossi dot com> |
State | Accepted |
Origin | http://rfc.zeromq.org/spec:22 |
Language¶
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119[#f1]_.
Goals¶
C4 is meant to provide a reusable optimal collaboration model for open source software projects. It has these specific goals:
- To maximize the scale of the community around a project, by reducing the friction for new Contributors and creating a scaled participation model with strong positive feedbacks;
- To relieve dependencies on key individuals by separating different skill sets so that there is a larger pool of competence in any required domain;
- To allow the project to develop faster and more accurately, by increasing the diversity of the decision making process;
- To support the natural life cycle of project versions from experimental through to stable, by allowing safe experimentation, rapid failure, and isolation of stable code;
- To reduce the internal complexity of project repositories, thus making it easier for Contributors to participate and reducing the scope for error;
- To enforce collective ownership of the project, which increases economic incentive to Contributors and reduces the risk of hijack by hostile entities.
Design¶
Preliminaries¶
- The project SHALL use the git distributed revision control system.
- The project SHALL be hosted on github.com or equivalent, herein called the “Platform”.
- The project SHALL use the Platform issue tracker.
- The project SHOULD have clearly documented guidelines for code style.
- A “Contributor” is a person who wishes to provide a patch, being a set of commits that solve some clearly identified problem.
- A “Maintainer” is a person who merge patches to the project. Maintainers are not developers; their job is to enforce process.
- Contributors SHALL NOT have commit access to the repository unless they are also Maintainers.
- Maintainers SHALL have commit access to the repository.
- Everyone, without distinction or discrimination, SHALL have an equal right to become a Contributor under the terms of this contract.
Licensing and Ownership¶
- The project SHALL use the GPLv2 or a variant thereof (LGPL, AGPL).
- All contributions to the project source code (“patches”) SHALL use the same license as the project.
- All patches are owned by their authors. There SHALL NOT be any copyright assignment process.
- The copyrights in the project SHALL be owned collectively by all its Contributors.
- Each Contributor SHALL be responsible for identifying themselves in the project Contributor list.
Patch Requirements¶
- Maintainers and Contributors MUST have a Platform account and SHOULD use their real names or a well-known alias.
- A patch SHOULD be a minimal and accurate answer to exactly one identified and agreed problem.
- A patch MUST adhere to the code style guidelines of the project if these are defined.
- A patch MUST adhere to the “Evolution of Public Contracts” guidelines defined below.
- A patch SHALL NOT include non-trivial code from other projects unless the Contributor is the original author of that code.
- A patch MUST compile cleanly and pass project self-tests on at least the principle target platform.
- A patch commit message SHOULD consist of a single short (less than 50 character) line summarizing the change, optionally followed by a blank line and then a more thorough description.
- A “Correct Patch” is one that satisfies the above requirements.
Development Process¶
- Change on the project SHALL be governed by the pattern of accurately identifying problems and applying minimal, accurate solutions to these problems.
- To initiate changes, a user SHOULD log an issue on the project Platform issue tracker.
- The user SHOULD write the issue by describing the problem they face or observe.
- The user SHOULD seek consensus on the accuracy of their observation, and the value of solving the problem.
- Users SHALL NOT log feature requests, ideas, suggestions, or any solutions to problems that are not explicitly documented and provable.
- Thus, the release history of the project SHALL be a list of meaningful issues logged and solved.
- To work on an issue, a Contributor SHALL fork the project repository and then work on their forked repository.
- To submit a patch, a Contributor SHALL create a Platform pull request back to the project.
- A Contributor SHALL NOT commit changes directly to the project.
- To discuss a patch, people MAY comment on the Platform pull request, on the commit, or elsewhere.
- To accept or reject a patch, a Maintainer SHALL use the Platform interface.
- Maintainers SHALL NOT accept their own patches.
- Maintainers SHALL NOT make value judgments on correct patches.
- Maintainers SHALL merge correct patches rapidly.
- The Contributor MAY tag an issue as “Ready” after making a pull request for the issue.
- The user who created an issue SHOULD close the issue after checking the patch is successful.
- Maintainers SHOULD ask for improvements to incorrect patches and SHOULD reject incorrect patches if the Contributor does not respond constructively.
- Any Contributor who has value judgments on a correct patch SHOULD express these via their own patches.
- Maintainers MAY commit changes to non-source documentation directly to the project.
Creating Stable Releases¶
- The project SHALL have one branch (“master”) that always holds the latest in-progress version and SHOULD always build.
- The project SHALL NOT use topic branches for any reason. Personal forks MAY use topic branches.
- To make a stable release someone SHALL fork the repository by copying it and thus become maintainer of this repository.
- Forking a project for stabilization MAY be done unilaterally and without agreement of project maintainers.
- A stabilization project SHOULD be maintained by the same process as the main project.
- A patch to a stabilization project declared “stable” SHALL be accompanied by a reproducible test case.
Evolution of Public Contracts¶
- All Public Contracts (APIs or protocols) SHOULD be documented.
- All Public Contracts SHOULD have space for extensibility and experimentation.
- A patch that modifies a stable Public Contract SHOULD not break existing applications unless there is overriding consensus on the value of doing this.
- A patch that introduces new features to a Public Contract SHOULD do so using new names.
- Old names SHOULD be deprecated in a systematic fashion by marking new names as “experimental” until they are stable, then marking the old names as “deprecated”.
- When sufficient time has passed, old deprecated names SHOULD be marked “legacy” and eventually removed.
- Old names SHALL NOT be reused by new features.
- When old names are removed, their implementations MUST provoke an exception (assertion) if used by applications.
Project Administration¶
- The project founders SHALL act as Administrators to manage the set of project Maintainers.
- The Administrators SHALL ensure their own succession over time by promoting the most effective Maintainers.
- A new Contributor who makes a correct patch SHALL be invited to become a Maintainer.
- Administrators MAY remove Maintainers who are inactive for an extended period of time, or who repeatedly fail to apply this process accurately.
Further Reading¶
- Argyris’ Models 1 and 2 - the goals of C4.1 are consistent with Argyris’ Model 2.
- Toyota Kata - covering the Improvement Kata (fixing problems one at a time) and the Coaching Kata (helping others to learn the Improvement Kata).
References¶
[1] | “Key words for use in RFCs to Indicate Requirement Levels” - http://tools.ietf.org/html/rfc2119 |
[2] | “Definition of a Free and Open Standard” - http://www.digistan.org/open-standard:definition |
[3] | “Consensus Oriented Specification System” - http://www.digistan.org/spec:1/COSS |
License¶
Original content licensed under the Creative Commons Attribution-Share Alike 3.0 License. (c) Copyright (c) 2007-2011 iMatix Corporation and Contributors.