TIP #0: Tcl Core Team Basic Rules

Title:Tcl Core Team Basic Rules
Version:$Revision: 2.6 $
Author:John Ousterhout <ouster at pacbell dot net>
Created:Monday, 11 December 2000


This TIP describes the mission, structure, and operating procedures of the Tcl Core Team (TCT). When in doubt about how the TCT works, consult this document as the final authority.


The Tcl Core Team is a self-organizing group of Tcl experts who are responsible for the evolution and management of the Tcl core. The Tcl Core Team decides what goes into releases; it implements, tests, and documents new features and bug fixes; it manages the release process; and it also manages the Tcl Developer Exchange Web site.

Scope: the Tcl core

The phrase "Tcl core" refers to the Tcl interpreter and the Tk toolkit (the packages previously released by Sun, Scriptics, and Ajuba). We also include the Tcl Developer Exchange Web site and the Tcl bug database in the Tcl core. The Tcl Core Team may also choose to take on additional responsibilities such as the creation of more comprehensive "batteries included" releases. We expect other Tcl development teams to form independently from the Tcl Core Team to manage additional projects, such as popular extensions. The Tcl Core Team may eventually spin off some of its activities into separate teams.

Team membership

The Tcl Core Team is a small group of people who are making major contributions to the development of the Tcl core and who are highly respected and trusted by the Tcl community. Team members are expected to invest significant amounts of their time to improve the Tcl core.

The original group of Team members was elected by the Tcl community, but the TCT now handles its own membership according to rules described here. To become a member of the Team you must be nominated by an existing member and voted on by the existing Team; you must receive 2/3 of the votes cast. If you would like to join the Tcl Core Team, you should first demonstrate your development skills and leadership by participating in development projects under the auspices of an existing team member.

Inactive or disruptive members of the team can be removed by a vote of other Team members: a 2/3 majority of those voting is required to remove a Team member.


The primary mechanism for communicating with the Tcl Core Team is the mail alias tcl-core@lists.sourceforge.net. This is a public mailing list; anyone interested in following the discussions of the TCT is welcome to join the mailing list. Email sent to this alias is archived, so you can review previous discussions at SourceForge.

Basic organizational structure

The team structure is simple and flat. All members have equal standing: there is no Chairman. The Tcl Core Team makes its own rules and chooses its own members as described in this document. Anyone on the Tcl Core Team can propose a change in the rules; after discussion, the change is voted on by the Team and must receive 2/3 of the votes cast. The person proposing a rules change is responsible for making sure that the change is properly implemented after it has been approved (e.g. by modifying this TIP, creating additional tools, etc.).

2/3 vote

Wherever a 2/3 vote is called for in this document, it means that a proposal must receive at least two-thirds of the votes cast, not votes from at least two-thirds of all TCT members.

Projects and maintainers

Tcl improvements are organized around two key ideas: projects and maintainers. Most of the activities of the Tcl Core Team consist of projects. A project can consist of a bug fix, a new feature in the Tcl core, a new facility in the Tcl Developer Exchange, or anything else except a change to this TIP. We divide projects into two general categories: bug fixes and feature changes. In general, if a project requires manual entries to be updated then it is a feature change; when in doubt, a project is a feature change . Bug fixes use a more streamlined process for implementation, whereas feature changes require discussion and approval in advance.

A maintainer is someone who has taken primary responsibility for a portion of the Tcl sources. Many maintainers will be members of the Tcl Core Team, but the Team may also select maintainers from outside the Tcl Core Team. We hope to find enough maintainers to cover all of the Tcl sources, but we will appoint a default maintainer to handle the parts of Tcl for which no other maintainer has volunteered. We'll also try to have backup maintainers who can step in when the primary maintainers are on vacation or otherwise unavailable.

A maintainer accepts several responsibilities, including the following:

Project life-cycle: approval, implementation, integration; TYANNOTT

The project for a feature change goes through three stages: approval, implementation, and integration.

A project starts when a member of the Tcl Core Team proposes it to the Team. Proposals are submitted by emailing TIPs (Tcl Improvement Proposals) to the Tcl Core Team. The format of TIPs is described in a separate TIP. Whoever proposes a project is responsible for making sure it is properly implemented. A proposal without a committed implementor cannot be approved.

Project approval is done through a process called TYANNOTT: Two Yesses And No No's Or Two Thirds. In order for a project to be approved it must have support from at least one other member of the Tcl Core Team besides the proposer. Once a project has been proposed and discussed, if there are no objections and there is a vote of confidence from a second team member ("Two Yesses And No No's"), then the project is approved. If objections remain after the discussion, then the proposer must summarize the objections and call for a vote of the TCT; a 2/3 vote is required for approval. The idea here is that most projects will be no-brainers and we want a simple decision process that doesn't get in the way of progress. On the other hand, the Tcl Core Team can only work effectively if it is highly collegial; if the Team can't reach pretty clear agreement on a project (i.e more than 1/3 of the TCT objects to it) then the project needs to be rethought.

The second phase of a project is implementation. The proposer is responsible for the implementation, either doing it himself/herself or arranging for someone else to do it. The implementation is done in a private work area and may not be integrated with the official sources until the third phase, below.

The third phase of a project is integrating the results back into the official Tcl repository. This is where maintainers come in. First, before any change can be applied to the official Tcl sources, the implementor must post it as a patch to the SourceForge patch manager. This rule applies regardless of the type of change (anything from a 1-line bug fix to a major new feature) and regardless of who is proposing the change. We use the SourceForge patch manager to record all changes and also to facilitate discussion about the changes before they are applied.

When a patch arrives in the SourceForge patch manager, the appropriate maintainer reviews it and works with the proposer to revise it as necessary. Other people can also review the patch, since it is public. If changes are needed, a revised patch is logged in the patch manager (the final version of the patch must always appear in the SourceForge patch manager). Once the maintainer is satisfied with the patch, it can be applied to the Tcl sources. If the patch implementor has write access to the sources that he or she can apply the patch once the maintainer has approved it. If the patch implementor doesn't have write access to the sources than the maintainer applies the patch.

Maintainers are responsible for watching the SourceForge patch manager to make sure that incoming patches in their area are dealt with quickly.

If the implementor of a patch is the maintainer, then he/she can apply the patch to the Tcl sources immediately after logging it in the SourceForge patch manager, without waiting for additional approval. However, if someone objects to the patch then the maintainer must be prepared to revise it after the fact.

Fast path for bug fixes

For a bug fix, no initial proposal or approval is required. The only approval needed is for the maintainer to review the patch before it is applied to the sources. For example, we invite everyone in the Tcl community to fix bugs and submit patches to the SourceForge patch manager.

Implementors outside the Tcl Core Team

We encourage people outside the Tcl Core Team to get involved with Tcl development. For example, anyone can submit patches for bug fixes. It's also fine for someone outside the Tcl core team to propose a feature change and then implement it, but there must be a sponsor on the Tcl Core Team who will take personal responsibility for it. Typically the sponsor will be the maintainer for the area of the change. It is the sponsor's responsibility to provide whatever level of supervision is appropriate to ensure that the project is executed well. If the implementor for a project is not a TCT member then they cannot vote for approval: TYANNOTT requires the sponsor plus one other Team member.

Raising concerns

If you have concerns about a project, the best time to raise them is during the initial discussion. Once a project has been approved, the best approach is to raise the issue directly with the implementor; most issues should get resolved quickly this way. If you can't find the implementor or can't reach agreement, and if the implementor is not a member of the Tcl Core Team, the next person to talk to is the Tcl Core Team member in charge of the project. If you still can't get satisfaction, then raise the issue with the entire Tcl Core Team by leading a discussion. Once all the issues are out, you can either withdraw your objection or summarize the issues (on both sides!) and call for a vote. If you aren't a member of the Tcl Core Team you will need to convince a Team member to manage the discussion and vote.

Even if a project has received initial approval, a Team member can object to the project later (e.g. if they believe it hasn't been implemented properly). If the objection isn't resolved there will be an additional vote of the Team, and the project cannot be applied to the official sources unless it receives a 2/3 majority of the votes cast. At the same time, Team members are expected to raise their objections as early as possible; it would be somewhat anti-social to raise a basic design objection late in the implementation of a project when it could have been raised during the initial approval.

Disagreements over patches

Normally, patches are not reviewed by the entire TCT; once the relevant maintainer has reviewed and approved them then they can be integrated. However, everyone is invited to review as many patches as they wish. If someone on the TCT objects to a patch and can't resolve the objection with the implementor and/or maintainer, then it gets discussed by the entire Tcl Core Team with the usual rules: if anyone on the Tcl Core Team has an objection that isn't resolved by the discussion, then a 2/3 vote is required to retain the patch. Thus if an implementor reaches a disagreement with a maintainer he/she can appeal to the entire Tcl Core Team. Or, if someone on the Tcl Core Team objects to a patch applied by a maintainer, they too can start a discussion in the whole team. The goal of the maintainer mechanism is to simplify and speed up improvements in the common case where everyone is in agreement, while still allowing the entire Tcl Core Team to offer input and resolve disagreements.

Changes that span areas

If a change involves several different areas of the Tcl sources, with different maintainers, then one of the maintainers acts as coordinator (presumably the one whose area has the most changes). It is their responsibility to consult with other maintainers whose areas are affected, so that all relevant maintainers are happy before the patch is applied to the sources.

Write access to the Tcl sources and the Web site

Everyone in the Tcl Core Team has write access to all the sources and the Web site, but they may only make changes consistent with approved projects. The Tcl Core Team can also give access to other people who are working on projects. For example, as part of a project proposal a Tcl Core Team member can propose that the work will be done by someone outside the team, and that that person should have write access for putting back changes. Giving out write access is part of a project decision, with the associated rules for approval. However, if someone outside the Tcl Core Team has write access, it must be under the auspices of a Tcl Core Team member; the Tcl Core Team member is personally responsible for making sure the project is completed satisfactorily and/or cleaning up any messes.

Deadlock resolution

If something should go wrong with the TCT organization and the Tcl Core Team deadlocks to a point where it can't make meaningful progress, then John Ousterhout will step in as benevolent dictator and make enough unilateral decisions to break the deadlock.


This document has been placed in the public domain.

Powered by Tcl[Index] [History] [HTML Format] [Source Format] [LaTeX Format] [Text Format] [XML Format] [*roff Format (experimental)] [RTF Format (experimental)]

TIP AutoGenerator - written by Donal K. Fellows