fix: resolve replay mode errors in Redis and Firestore no-op request handlers

[sohankshirsagar]

Summary

Fixes two bugs in replay mode that cause crashes when background requests hit the noOpRequestHandler path in handleReplayMode. A customer reported TypeError: Expected result to be array of values from rate-limit-redis and Error: Original doc function not available from Firestore during replay.

Changes

• Redis: Return type-appropriate defaults from sendCommand and commandsExecutor no-op handlers.
  Previously both returned undefined, which breaks callers that validate the response type. For example, rate-limit-redis uses EVALSHA and strictly expects an array result — receiving undefined throws TypeError: Expected result to be array of values. Now returns [] for EVAL/EVALSHA commands and null (standard Redis nil) for everything else.
• Firestore: Fix this/self scoping bug in collection.add no-op handler.
  The noOpRequestHandler arrow function captured this from the enclosing regular function, which binds to the CollectionReference instance — not the FirestoreInstrumentation instance where originalCollectionDocFn is stored. Changed this.originalCollectionDocFn → self.originalCollectionDocFn so the property lookup hits the instrumentation class. The .call(this, "") argument correctly remains this (the CollectionReference context).\

Context

The Redis error specifically surfaces when rate-limit-redis express middleware fires during replay. The rate limiter's Redis calls land on the no-op path because they execute before/outside the SDK's HTTP span context, so handleReplayMode classifies them as background requests. The no-op handler just needs to return a value that won't crash the caller — the rate limiter effectively becomes a pass-through in replay mode.
The Firestore error surfaces from AMQP consumer jobs (ch.consume) that write to Firestore outside of any traced HTTP request — these are genuine background requests where the no-op path is the correct behavior, but the this/self bug prevented it from working.

[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src/instrumentation/libraries/firestore/Instrumentation.ts">

<violation number="1" location="src/instrumentation/libraries/firestore/Instrumentation.ts:706">
P1: Calling Firestore `doc("")` here can still throw in replay mode. Use `doc()` with no argument so the no-op path returns an auto-ID `DocumentReference` instead of an invalid empty document path.</violation>
</file>

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Commit	Status	Output	Created (UTC)
b450cc5	Generated 13 tests - 13 passed	Tests	Mar 13, 2026 9:39PM
3665f12	Tusk is paused for this PR	Output	Mar 13, 2026 9:51PM