MSC4210: Remove legacy mentions

[tulir]

Rendered

Implementations:

• Synapse: Implement MSC4210: Remove legacy mentions element-hq/synapse#17783
• Conduwuit: https://github.com/girlbossceo/conduwuit/commit/60d84195c51c523b965c17d75ebca861290260e5 + https://github.com/girlbossceo/ruwuma/commit/39c1addd37a4eed612ac1135edc2cccd9d331d5e

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FCP tickyboxes

MSC checklist

[anoadragon453]

For the "needs-implementation" label on this MSC, one could consider implementation as "removing support for legacy mentions". However, I doubt a client will actually remove backwards-compatibility support for a feature until it's official removed from the spec. So it seems we're at a stalemate.

In the interest of unblocking it, I propose moving forwards with this MSC. The amount of client implementation shown in #4210 (comment) demonstrates to me that the ecosystem is ready to move forwards.

@mscbot fcp merge

[mscbot]

Team member @mscbot has proposed to merge this. The next step is review by the rest of the tagged people:

• @clokep
• @dbkr
• @uhoreg
• @turt2live
• @ara4n
• @anoadragon453
• @richvdh
• @tulir
• @erikjohnston
• @KitsuneRal

Concerns:

• may break notifications for too many users
• checklist not completed

Once at least 75% of reviewers approve (and there are no outstanding concerns), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for information about what commands tagged team members can give me.

[turt2live]

MSCs proposed for Final Comment Period (FCP) should meet the requirements outlined in the checklist prior to being accepted into the spec. This checklist is a bit long, but aims to reduce the number of follow-on MSCs after a feature lands.

SCT members: please check off things you check for, and raise a concern against FCP if the checklist is incomplete. If an item doesn't apply, prefer to check it rather than remove it. Unchecking items is encouraged where applicable.

Checklist:

• Are appropriate implementation(s)
  specified in the MSC’s PR description?
• Are all MSCs that this MSC depends on already accepted?
• For each new endpoint that is introduced:
  • Have authentication requirements been specified?
  • Have rate-limiting requirements been specified?
  • Have guest access requirements been specified?
  • Are error responses specified?
    • Does each error case have a specified errcode (e.g. M_FORBIDDEN) and HTTP status code?
      • If a new errcode is introduced, is it clear that it is new?
• Will the MSC require a new room version, and if so, has that been made clear?
  • Is the reason for a new room version clearly stated? For example,
    modifying the set of redacted fields changes how event IDs are calculated,
    thus requiring a new room version.
• Are backwards-compatibility concerns appropriately addressed?
• Are the endpoint conventions honoured?
  • Do HTTP endpoints use_underscores_like_this?
  • Will the endpoint return unbounded data? If so, has pagination been considered?
  • If the endpoint utilises pagination, is it consistent with
    the appendices?
• An introduction exists and clearly outlines the problem being solved.
  Ideally, the first paragraph should be understandable by a non-technical audience.
• All outstanding threads are resolved
  • All feedback is incorporated into the proposal text itself, either as a fix or noted as an alternative
• While the exact sections do not need to be present,
  the details implied by the proposal template are covered. Namely:
  • Introduction
  • Proposal text
  • Potential issues
  • Alternatives
  • Dependencies
• Stable identifiers are used throughout the proposal, except for the unstable prefix section
  • Unstable prefixes consider the awkward accepted-but-not-merged state
  • Chosen unstable prefixes do not pollute any global namespace (use “org.matrix.mscXXXX”, not “org.matrix”).
• Changes have applicable Sign Off from all authors/editors/contributors
• There is a dedicated "Security Considerations" section which detail
  any possible attacks/vulnerabilities this proposal may introduce, even if this is "None.".
  See RFC3552 for things to think about,
  but in particular pay attention to the OWASP Top Ten.

[turt2live]

@mscbot concern checklist not completed

[turt2live]

generally this lgtm

[turt2live]

@mscbot concern may break notifications for too many users

[turt2live]

@mscbot resolve may break notifications for too many users

[richvdh]

@mscbot resolve checklist not completed

[mscbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[mscbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.