tor-parallel-relay-conn/doc/spec/proposals/001-process.txt

Filename: 001-process.txt
Title: The Tor Proposal Process
Version: $Revision: 11537 $
Last-Modified: $Date: 2007-01-26T19:04:29.998860Z $
Author: Nick Mathewson
Created: 30-Jan-2007
Status: Meta

Overview:

   This document describes how to change the Tor specifications, how Tor
   proposals work, and the relationship between Tor proposals and the
   specifications.

   This is an informational document.

Motivation:

   Previously, our process for updating the Tor specifications was maximally
   informal: we'd patch the specification (sometimes forking first, and
   sometimes not), then discuss the patches, reach consensus, and implement
   the changes.

   This had a few problems.

   First, even at its most efficient, the old process would often have the
   spec out of sync with the code.  The worst cases were those where
   implementation was deferred: the spec and could stay out of sync for
   versions at a time.

   Second, it was hard to participate in discussion, since you had to know
   which portions of the spec were a proposal, and which were already
   implemented.

   Third, it littered the specifications with too many inline comments.
     [This was a real problem -NM]
       [Especially when it went to multiple levels! -NM]
         [XXXX especially when they weren't signed and talked about that
          thing that you can't remember after a year]

How to change the specs now:

   First, somebody writes a proposal document.  It should describe the change
   that should be made in detail, and give some idea of how to implement it.
   Once it's fleshed out enough, it becomes a proposal.

   Like an RFC, every proposal gets a number.  Unlike RFCs, proposals can
   change over time and keep the same number.  The history for each proposal
   will be stored in the Tor Subversion repository.

   Once a proposal is in the repository, we should discuss and improve it
   until we've reached consensus that it's a good idea, and that it's
   detailed enough to implement.  When this happens, we implement the
   proposal and incorporate it into the specifications.  Thus, the specs
   remain the canonical documentation for the Tor protocol: no proposal is
   ever the canonical documentation for an implemented feature.

   {It's still okay to make mall changes to the spec if the code can be
   written more or less immediately, or cosmetic changes if no code change is
   required.  This document reflects the current developers' _intent_, not
   a permanent promise to always use this process in the future: we reserve
   the right to get really excited and run off and implement something in a
   caffeine-and-m&m-fueled all-night hacking session.}

Proposal status:

   Open: A proposal under discussion.

   Accepted: The proposal is complete, and we intend to implement it.

   Finished: The proposal has been accepted and implemented.

   Closed: The proposal has been accepted, implemented, and merged into the
      main specification documents.

   Rejected: We're not going to implement the feature as described here,
      though we might do some other version.  See comments in the document
      for details.

   Needs-Revision: The idea for the proposal is a good one, but the proposal
      as it stands has serious problems that keep it from being accepted.
      See comments in the document for details.

   Dead: The proposal hasn't been touched in a long time, and it doesn't look
      like anybody is going to complete it soon.  It can become "Open" again
      if it gets a new proponent.

   Needs-Research: There are research problems that need to be solved before
      it's clear whether the proposal is a good idea.

   Meta: This is not a proposal, but a document about proposals.

Proposal numbering:

   Numbers 000-099 are reserved for special and meta-proposals.  100 and up
   are used for actual proposals.  Numbers aren't recycled.

What should go in a proposal:

   Every proposal should have a header containing these fields:
     Filename, Title, Version, Last-Modified, Author, Created, Status.
   The Version and Last-Modified fields should use the SVN Revision and Date
   tags respectively.

   The body of the proposal should start with an Overview section explaining
   what the proposal's about, what it does, and about what state it's in.

   After the Overview, the proposal becomes more free-form.  Depending its
   the length and complexity, the proposal can break into sections as
   appropriate, or follow a short discursive format.  Every proposal should
   contain at least the following information before it can be "ACCEPTED",
   thought the information does not need to be in sections with these names.

      Motivation: What problem is the proposal trying to solve?  Why does
        this problem matter?  If several approaches are possible, why take this
        one?

      Design: A high-level view of what the new or modified features are, how
        the new or modified features work, how they interoperate with each
        other, and how they interact with the rest of Tor.  This is the main
        body of the proposal.  Some proposals will start out with only a
        Motivation and a Design, and wait for a specification until the
        Design seems approximately right.

      Security implications: What effects might the proposed changes have on
        anonymity, how well understood these effects are, and so on.

      Specification: A detailed description of what needs to be added to the
        Tor specifications in order to implement the proposal.  This should
        be in about as much detail as the specifications will eventually
        contain: it should be possible for independent programmers to write
        mutually compatible implementations of the proposal based on its
        specifications.

      Compatibility: Will versions of Tor that follow the proposal be
        compatible with versions that do not?  If so, how will compatibility
        me achieved?  Generally, we try to not to drop compatibility if at
        all possible; we haven't made a "flag day" change since 2003 or
        earlier, and we don't want to do another one.  [XXX is this true?]

      Implementation: If the proposal will be tricky to implement in Tor's
        current architecture, the document can contain some discussion of how
        to go about making it work.

      Performance and scalability notes: If the feature will have an effect
        on performance (in RAM, CPU, bandwidth) or scalability, there should
        be some analysis on how significant this effect will be, so that we
        can avoid really expensive performance regressions, and so we can
        avoid wasting time on insignificant gains.