🚅 Deployed to the rivet-pr-4976 environment in rivet-frontend

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• refactor(depot-client): split embedded depot transport #4970 : 2 dependent PRs (#4971 , #4972 )
• fix(rivetkit): decode legacy v4 actor schedule args #4976 👈 (View in Graphite)
• fix(engine): install rustls provider with pools #4975
• fix(rivetkit): defer initialized persist until state exists #4974
• test(rivetkit): cover failed preflight disconnect handling #4973
• fix(rivetkit): hide pending connections during preflight #4969
• WIP: more fuzz tests #4962
• fix(rivetkit): wrap onMigrate in savepoints #4960 : 1 other dependent PR (#4963 )
• fix(pegboard): align drain grace defaults with stop threshold #4958 : 1 other dependent PR (#4966 )
• fix(rivetkit): preserve bridge error messages #4959
• fix(rivetkit): fire abort signal on shutdown finalize #4957
• fix(rivetkit): use startup kv preload #4956
• fix(client): flatten skipReadyWait option #4955
• ci(publish): add manual preview publish flow #4954
• fix(depot): add ltx decode diagnostics #4953
• fix(universaldb): preserve plain set values #4952
• fix(universaldb): align versionstamp operand encoding #4951
• fix(rivetkit): export database provider types #4950
• wip: kitchen sink agentic loop finish #4949
• chore(rivetkit): note duplicate admission logic #4948
• test(rivetkit): cover bypass fetch header forwarding #4947
• feat(kitchen-sink): add actor probe controls #4946
• fix(gateway): split actor response wait errors #4945
• fix(guard): handle bypass preflight before query parse #4944
• feat(kitchen-sink): add mock agent event log copy #4943
• fix(kitchen-sink): default mock agent to local endpoint #4942
• test(rivetkit): enable driver lifecycle regressions #4941
• test(rivetkit): verify cached websocket db refs exceed grace #4940
• fix(rivetkit-core): keep sleeping actors reachable during grace #4939
• test(rivetkit): cover async websocket close db access #4938
• fix(rivetkit): keep actors awake until keepAwake work finishes #4937
• fix(rivetkit): persist native onSleep state on errors #4936
• fix(rivetkit-core): allow dispatch during sleep grace #4935
• fix(rivetkit): make duplicate sleep requests idempotent #4934
• main

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Code Review: fix(rivetkit): decode legacy v4 actor schedule args

Overview

Targeted production hotfix adding a fallback decoder for v4 actor persist payloads written by a short-lived buggy writer that stored ScheduleEvent.args as raw data instead of optional Cbor. The fix is well-scoped and the approach is sound.

What Works Well

• Canonicality round-trip check is the right way to guard against serde_bare accepting nonzero bools as true. The logic is clean and correct.
• Local struct definitions (LegacyRawV4Actor, LegacyRawV4ScheduleEvent) inside the function are appropriate here - single-use legacy types that should not pollute the module namespace.
• Field mapping is correct: BARE is positionally encoded, so renaming timestamp_ms in the legacy struct is cosmetic-only and does not affect decoding.
• Empty args handling: (!event.args.is_empty()).then_some(event.args) correctly normalizes an empty legacy raw payload to None.
• Tests use raw bytes from actual production payloads, which is the right approach for format regression tests.

Issues / Suggestions

1. Ambiguous error when v4 decodes non-canonically and legacy also fails

When current v4 decodes successfully but is non-canonical (current_error = None) and the legacy decoder also fails, the returned error is legacy_error. This gives no signal that v4 did decode but failed the round-trip check. A tracing::warn! when the non-canonical case is hit would make the path visible in production logs.

2. Missing happy-path and error-path test coverage

The two tests cover the production legacy payload and the non-canonical v4 acceptance case. Missing:

• A canonical current-v4 payload that should decode via the fast path without hitting the legacy fallback. This ensures the round-trip check correctly admits valid current actors without regressing them.
• An invalid payload that should fail both decoders, to verify the error path returns something sensible.

3. serde_bare::to_vec failure is silently treated as non-canonical

If serialization fails (e.g. OOM), is_ok_and returns false and falls through to the legacy decoder. This is safe but silently discards the serialization error. A tracing::warn from point 1 would cover this case too.

Summary

The fix is correct and safe for the stated production issue. The three points above are minor: the logging suggestion would improve debuggability, and the additional test cases would harden the regression suite. None are blockers for a production mitigation. LGTM with the logging suggestion as a nice-to-have.

Preview packages published to npm

Install with:

npm install rivetkit@pr-4976

All packages published as 0.0.0-pr.4976.554eccf with tag pr-4976.

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-554eccf
docker pull rivetdev/engine:full-554eccf

npm install rivetkit@pr-4976
npm install @rivetkit/react@pr-4976
npm install @rivetkit/rivetkit-napi@pr-4976
npm install @rivetkit/workflow-engine@pr-4976