fix(api): make actor destroy wait for ack

[MasterPtato]

Description

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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?

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Checklist:

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[MasterPtato]

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• chore: bump rivetkit protocol version #4329
• fix(udb): add txn tagging #4328
• fix(api): make actor destroy wait for ack #4327 👈 (View in Graphite)
• chore: flatten runtime config #4326
• chore: deploy patch #4324
• main

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[claude]

PR Review: fix(api): make actor destroy wait for ack

The fix is correct and the approach is sound. A few observations:

Correct subscription ordering. Subscribing to DestroyComplete before sending the Destroy signal eliminates the race where the event could be emitted between sending the signal and setting up the subscription. This is the right pattern.

Parallel fetching. Running actor::get and namespace::resolve_for_name_global concurrently with tokio::try_join! is a nice incidental improvement.

Explicit destroy_ts guard. The early return on actor.destroy_ts.is_some() is important for correctness: without it, an already-destroyed actor would still proceed past validation, send a signal that returns None (workflow gone), skip destroy_sub.next(), and succeed silently. Now it returns NotFound consistently, which matches caller expectations.

---

Concerns:

No timeout on destroy_sub.next().await?. If the destroy workflow stalls (stuck activity, infrastructure issue), this call will hang until the request times out at a higher level. If there is no upstream request timeout, the call hangs indefinitely. Consider wrapping with tokio::time::timeout and returning an appropriate error.

Concurrent delete requests sharing the same DestroyComplete event. If two requests concurrently delete the same actor, both subscribe to the topic before sending the signal. The first sends Destroy and triggers the workflow; the second may also get res = Some(...) (workflow still alive at signal time), so both enter the else branch and call destroy_sub.next().await?. Whether both subscribers receive the event depends on the pub/sub semantics of ctx.subscribe. If the message is consumed rather than broadcast, one caller could hang. Worth verifying.

Subscription created before validation. The subscription is set up unconditionally before confirming the actor exists or belongs to the right namespace. Requests that fail validation create and immediately drop a subscription. This is minor overhead but should be fine assuming subscription setup has no significant server-side cost.

---

Minor: The PR description template was not filled in. It would help to note the user-visible behavior change (DELETE now blocks until the actor is fully torn down) and any impact on clients that expect a fast response.

[pkg-pr-new]

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commit: 96bf39a

[MasterPtato]

This change is part of the following stack:

• chore: deploy patch #4324
  • chore: flatten runtime config #4326
    • fix(api): make actor destroy wait for ack #4327 ◀
      • fix(udb): add txn tagging #4328
        • chore: bump rivetkit protocol version #4329
          • fix(ups): formalize subjects #4334
            • fix(api): properly dedup name list responses #4337
              • fix(pb): clear actor reschedule ts on alloc #4338
            • fix(ups): add metrics #4368

_{Change managed by git-spice.}