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WebAssembly W3C Process

This file describes how feature proposals will progress through the standardization process.

A feature is a substantial change to WebAssembly, such that it for example requires additional opcodes, types, tests, or module sections. See case #3 here.

Something is definitely a feature if it:

  • Adds an opcode or other pieces of abstract syntax
  • Changes or extends the binary format
  • Changes or extends the text format
  • Requires adding or changing tests
  • Requires extending or changing the reference interpreter

Something is out-of-scope if it doesn't fit the WebAssembly Working Group's charter and there's agreement that the charter should not be amended to cover the proposal.

In general, the process moves forward through a series of numbered phases. However, if issues are uncovered or consensus devolves, proposals should back up to the appropriate prior step.

0. Pre-Proposal [Individual Contributor]

Entry requirements:

  • A Community Group member has an idea. Notably, no CG vote is required to begin phase 0.

During this phase:

  1. An issue is filed on the design repository to present the idea.
  2. Discussion on the feature occurs on the issue.
  3. A champion or champions emerge. They may add the proposal to the proposal list at phase 0.
  4. The champion(s) put together a somewhat-formal description of the feature in their own GitHub repository or on the issue.
  5. An item is added to the bi-weekly Community Group video calls's agenda through a pull request.
  6. The CG votes on general interest in this proposal. Consensus requirements are low: do members believe that the feature is in-scope and will plausibly be workable?

1. Feature Proposal [Community Group]

Entry requirements:

  • The pre-proposal vote has succeeded.

During this phase:

  1. If the proposal is not already listed, it should be added to the proposal list at this time.
  2. A new repository, forking the spec repo, is created by one of the WebAssembly organization administrators, or transfered to the WebAssembly organization by the champion.
  3. The champion will attempt to reach broad consensus in the Community Group.
  4. Pull requests and issues are used to iterate on the design of the feature. Specifically, the spec text must be in a reasonably complete state before attempting to move to phase 2.
  5. If relevant to demonstrate the viability of a feature, prototype implementations of the feature are implemented by interested embedders (possibly on a branch).

2. Proposed Spec Text Available [Community + Working Group]

Entry requirements:

  • Full proposed English spec text available in a forked repo around which a reasonably high level of consensus exists.
  • Updates to the formal notation, test suite, and reference interpreter are NOT yet required.

During this phase:

  • One or more implementations proceed on prototyping the feature to the point that a comprehensive set of tests can be added.
  • A test suite is added. These tests need not pass the reference interpreter at this point, but should pass on some implementation.

3. Implementation Phase [Community + Working Group]

Entry requirements:

  • Test suite has been updated to cover the feature in its forked repo.
  • The test suite should run against some implementation, though it need not be the reference interpreter.
  • Formal notation in the spec need not be updated.

During this phase, the following proceeds in parallel:

  • Embedders implement the feature.
  • The forked repo is updated to include revisions to the formalization.
  • The forked repo spec is updated to include implementation of the feature in the reference interpreter.
  • The feature is implemented in toolchains.

4. Standardize the Feature [Working Group]

Entry requirements:

  • Two or more Web VMs implement the feature.
  • At least one toolchain implements the feature.
  • The formalization and the reference interpreter are usually updated (though these two can be done as part of step 3 at the Working Group chair's discretion).
  • Community Group has reached consensus in support of the feature.
  • NOTE: By this point the proposal is basically frozen, since the Community Group is the sole venue where substantial work can occur.

At this point:

  • The feature is fully handed off to the Working Group.
  • During this phase, Working Group members discuss the feature, consider edge cases, and work to confirm consensus that the feature is now complete.
  • Periodically, the Working Group will hold polls on how "ship worthy" the feature is, in order to help browsers to make decisions about when to ship.
  • Only minor cosmetic changes occur at this point. If substantial changes are deemed required, the feature is sent back to the Community Group.

5. The Feature is Standardized [Working Group]

Entry requirements:

  • Consensus is reached in amongst Working Group members that the feature is complete.

When Working Group consensus is reached (online), editors can merge the feature into master on the spec repo. The W3C snapshots (for REC) are made at a regular cadence (in a W3C repo), used to stamp official version. Matching tags are added in the github spec repo.


Who owns the various existing W3C repos?

They are owned in common by the Working + Community Groups. The Working Group uses the repo to iterate on finalized proposals for hand-off to the W3C's snapshotted copy of the spec. The other repos are primarily overseen by the Community Group.

What about licenses?

The spec and spec forks will move to a W3C Software and Document Notice and License. Other related repos for prototypes + tools will continue under their respective licenses.

What is the Community Group for?

Incubation. To provide a safe harbor for a broad set of stakeholders to discuss, design, and iterate on new features during Steps 1-3 above. It should attempt to address all concerns, but need not reach 100% consensus.

What is the Working Group for?

To finalize and ratify mostly complete specs + test suites from the Community Group. Changes to the spec need not have reached full consensus in the Community Group to move to the Working Group, but key Working Group stakeholders should resolve outstanding mismatch in the Community Group.

Who will have admin rights + close issues etc?

This can be distributed and handled by multiple folks. In terms of github issues specifically, chairs will mainly step in to drive consensus, keep discussions civil, and as a first escalation point if someone is unhappy with how the collaboration is conducted (for instance if someone is unhappy a particular issue was closed over their objections). This is a general part of their role in community building: