fix(api): subscribe before namespace workflow dispatch

[NathanFlurry]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[NathanFlurry]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• chore(rivetkit): remove inline tests #4668
• fix(guard): serialize gateway actor keys correctly #4655
• fix(api): subscribe before namespace workflow dispatch #4654 👈 (View in Graphite)
• fix(rivetkit): restore hibernatable sockets and hydrate serverless starts #4658
• fix(rivetkit-native): expose full hibernation metadata to JS #4657
• fix(pegboard): persist and replay hibernating requests #4656
• fix(rivetkit): keep internal error exposure behavior consistent #4661
• test(rivetkit): stabilize actor db driver tests #4664
• fix(test): stabilize lifecycle, sleep, queue, and run edge cases #4660 : 1 other dependent PR (#4665 )
• test(rivetkit): re-enable gateway URL and direct-registry coverage #4659
• fix(rivetkit): add lifecycle error retry and gateway HTTP routing #4666
• chore(engine): publish engine bases in ci #4649 : 2 other dependent PRs (#4650 , #4652 )
• chore: lockfile lefthook #4647
• fix(rivetkit): surface native sqlite kv errors to callers #4645
• fix(rivetkit): prevent sleep races during disconnect and db work #4644
• fix(rivetkit): isolate engine envoys and propagate startup failures #4643
• test(rivetkit): remove wasm sqlite-only fixtures and coverage #4642
• chore(sqlite-vfs): remove wasm sqlite packages and workspace wiring #4641
• chore(rivetkit): remove wasm sqlite runtime #4614
• fix(sqlite-native): restore native startup kv preload #4639
• fix(sqlite-native): delete metadata before chunk range #4638
• fix(sqlite-native): keep truncate cache coherent #4637
• fix(sqlite-vfs): use delete range for truncate cleanup #4636
• fix(sqlite-native): restore kv error hook #4635
• perf(sqlite-native): avoid cloning cached read chunks #4634
• perf(sqlite-native): gate kv operation labels #4633
• perf(sqlite-native): reuse read cache for partial writes #4632
• perf(sqlite-native): remove delete file existence probe #4631
• fix(sqlite-native): gate native read cache behind env var #4630
• fix(pegboard): isolate runner config dc lookup failures #4625 : 1 other dependent PR (#4626 )
• docs(pegboard): note runner config upsert split write risk #4624
• fix(pegboard): unpack global runner config keys correctly #4623
• fix(pegboard-gateway): enforce tunnel message state #4622
• fix(pegboard-runner): clear terminal tunnel routes #4621
• fix(pegboard): skip protocol version keys in runner pool backfill #4620
• fix(pegboard): create missing normal runner configs #4619
• fix(epoxy): reuse cached optimistic value #4618
• main

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[claude]

PR Review: fix(api): subscribe before namespace workflow dispatch

Overview: This is a small but important race condition fix in the namespace creation API handler. The change reorders two operations in the create function in engine/packages/api-peer/src/namespaces.rs.

Before: Dispatch workflow then subscribe to events. After: Subscribe to events then dispatch workflow.

The Bug: This is a classic subscribe-before-publish race condition. In the original code, the workflow was dispatched first, then subscriptions were set up for CreateComplete and Failed events. If the workflow completed between those two steps, the event would be missed, causing the API call to hang indefinitely. This is especially likely on fast paths where the workflow completes quickly.

Code Quality: The fix is minimal and targeted. The logic of the tokio::select! block is unchanged. No new warnings or dependencies introduced.

Correctness: The fix is correct. The subscription mechanism buffers or replays events that occur after subscription is established but before next() is called, so there is no lost-event window.

Minor note: if dispatch().await? errors after subscriptions are set up, create_sub and fail_sub are dropped without being consumed. This is not a regression but worth verifying the subscription type cleans up correctly on drop.

Verdict: The fix is correct and well-scoped. This addresses a real race condition that could cause API calls to hang non-deterministically. No issues with the implementation.

Note: The PR description checklist is not filled out and this PR is still in Draft state.

[github-actions]

Preview packages published to npm

Install with:

npm install rivetkit@pr-4654

All packages published as 0.0.0-pr.4654.8f47e27 with tag pr-4654.

Engine binary is shipped via @rivetkit/engine-cli on linux-x64-musl, linux-arm64-musl, darwin-x64, and darwin-arm64. Windows users should use the release installer or set RIVET_ENGINE_BINARY.

Docker images:

docker pull rivetdev/engine:slim-8f47e27
docker pull rivetdev/engine:full-8f47e27

Individual packages

npm install rivetkit@pr-4654
npm install @rivetkit/react@pr-4654
npm install @rivetkit/rivetkit-native@pr-4654
npm install @rivetkit/workflow-engine@pr-4654