Return better error when client tries to join non-existent room #1604

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nex merged 1 commit from ezera/continuwuity:ezera/joining-nonexistent-room-error into main 2026-04-05 17:04:50 +00:00

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ezera commented 2026-04-01 17:48:32 +00:00

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Previously: #1579

---

This pull request changes the error returned by the server when the user attempts to join a non-existent room (see #1443). Previously, the server returned error 500. Now, we return error 404, with a generic error message, which is closer to what Synapse does (as stated in #1443).

I considered returning

403 M_UNKNOWN or other generic message (prevent malicious users to enumerate room ids this way)

because I agree that it would make sense to prevent someone from enumerating which rooms exist. However, I settled on 404, because I thought it would make sense to mimic Synapse for the sake of client compatibility. Please let me know if you disagree.

I also defined a new err! macro arm. I wasn't sure that was the best idea, but there didn't seem to be an existing arm that fit for returning this kind of error.

I ran the tests locally, and everything passed, but I haven't added a test for this specific case.

Fixes: #1443

Pull request checklist:

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  main.
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    myself, if applicable. This includes ensuring code compiles.
  • My commit messages follow the commit message format and are descriptive.
  • I have written a news fragment for this PR, if applicable.

Previously: #1579 --- <!-- In order to help reviewers know what your pull request does at a glance, you should ensure that 1. Your PR title is a short, single sentence describing what you changed 2. You have described in more detail what you have changed, why you have changed it, what the intended effect is, and why you think this will be beneficial to the project. If you have made any potentially strange/questionable design choices, but didn't feel they'd benefit from code comments, please don't mention them here - after opening your pull request, go to "files changed", and click on the "+" symbol in the line number gutter, and attach comments to the lines that you think would benefit from some clarification. --> This pull request changes the error returned by the server when the user attempts to join a non-existent room (see https://forgejo.ellis.link/continuwuation/continuwuity/issues/1443). Previously, the server returned error 500. Now, we return error 404, with a generic error message, which is closer to what Synapse does (as stated in #1443). I considered returning > 403 M_UNKNOWN or other generic message (prevent malicious users to enumerate room ids this way) because I agree that it would make sense to prevent someone from enumerating which rooms exist. However, I settled on 404, because I thought it would make sense to mimic Synapse for the sake of client compatibility. Please let me know if you disagree. I also defined a new `err!` macro arm. I wasn't sure that was the best idea, but there didn't seem to be an existing arm that fit for returning this kind of error. I ran the tests locally, and everything passed, but I haven't added a test for this specific case. <!-- Example: This pull request allows us to warp through time and space ten times faster than before by double-inverting the warp drive with hyperheated jump fluid, both making the drive faster and more efficient. This resolves the common issue where we have to wait more than 10 milliseconds to engage, use, and disengage the warp drive when travelling between galaxies. --> <!-- Closes: #... --> Fixes: #1443 <!-- Uncomment the above line(s) if your pull request fixes an issue or closes another pull request by superseding it. Replace `#...` with the issue/pr number, such as `#123`. --> **Pull request checklist:** <!-- You need to complete these before your PR can be considered. 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This includes ensuring code compiles. - [x] My commit messages follow the [commit message format][c1cm] and are descriptive. - [x] I have written a [news fragment][n1] for this PR, if applicable<!--(can be done after hitting open!)-->. <!-- Notes on these requirements: - While not required, we encourage you to sign your commits with GPG or SSH to attest the authenticity of your changes. - While we allow LLM-assisted contributions, we do not appreciate contributions that are low quality, which is typical of machine-generated contributions that have not had a lot of love and care from a human. Please do not open a PR if all you have done is asked ChatGPT to tidy up the codebase with a +-100,000 diff. - In the case of code style violations, reviewers may leave review comments/change requests indicating what the ideal change would look like. 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ezera added 2 commits 2026-04-01 17:48:32 +00:00

fix: return 404 when joining non-existent room ... f740be422d

Fixes #1443.

refactor: clarify error msg on joining uknown room 1326e33fc5

ezera changed title from ezera/joining-nonexistent-room-error to WIP ezera/joining-nonexistent-room-error 2026-04-01 17:48:43 +00:00

nex added the

Enhancement

Matrix/Client

labels 2026-04-01 17:48:47 +00:00

ezera force-pushed ezera/joining-nonexistent-room-error from 1326e33fc5 to e78afffdc8 2026-04-01 17:52:58 +00:00 Compare

ezera changed title from WIP ezera/joining-nonexistent-room-error to ezera/joining-nonexistent-room-error 2026-04-01 17:53:11 +00:00

ezera requested review from nex 2026-04-01 17:53:16 +00:00

ezera force-pushed ezera/joining-nonexistent-room-error from e78afffdc8 to d8e2ad89b7 2026-04-01 18:05:24 +00:00 Compare

ezera changed title from ezera/joining-nonexistent-room-error to Return better error when client tries to join non-existent room 2026-04-01 18:07:03 +00:00

ezera force-pushed ezera/joining-nonexistent-room-error from d8e2ad89b7 to d4ef7dad92 2026-04-01 18:13:17 +00:00 Compare

Jade approved these changes 2026-04-02 19:54:23 +00:00

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Looks OK to me

Looks OK to me

🎉 1

Jade added the

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label 2026-04-02 19:54:39 +00:00

nex approved these changes 2026-04-05 13:25:22 +00:00

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Awesome, thank you!

Awesome, thank you!

nex scheduled this pull request to auto merge when all checks succeed 2026-04-05 13:25:48 +00:00

ezera force-pushed ezera/joining-nonexistent-room-error from d4ef7dad92 to 59fc1fccb5 2026-04-05 16:35:44 +00:00 Compare

ezera force-pushed ezera/joining-nonexistent-room-error from 59fc1fccb5 to 67d8d72506 2026-04-05 16:41:23 +00:00 Compare

nex merged commit 67d8d72506 into main 2026-04-05 17:04:50 +00:00

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