test(serverless): avoid pinning header validation order

[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]

• fix(rivetkit): drain shutdown work before sleep #4902 : 2 dependent PRs (#4903 , #4904 )
• feat(sqlite): wire remote sqlite execute handlers #4897
• test(serverless): avoid pinning header validation order #4896 👈 (View in Graphite)
• chore(driver-test-runner): add native/wasm runtime matrix to skill #4884 : 3 other dependent PRs (#4892 , #4894 , #4901 )
• chroe: rename rivetkit-sqlite to depot-client #4883
• fix(rivetkit-wasm): fix mem leaks #4880
• chore(rivetkit): wasm support #4860
• feat(sqlite): add cold read benchmarks and simplify optimizations #4857
• feat(sqlite): benchmark cold reads #4848 : 1 other dependent PR (#4864 )
• docs(actors): document manual lifecycle controls #4847
• test(sqlite): expand db stress coverage #4846 : 1 other dependent PR (#4849 )
• test(raw-websocket): add serverless smoke coverage #4845
• feat(serverless): configure drain grace period #4844
• fix(publish): enable frontend build for engine target and use turbo build instead of turbo build:engine #4843
• feat(rivetkit): expose conn handle in onWebSocket context #4842
• fix(rivetkit): normalize waitUntil/keepAwake promises to null to avoid serde undefined error #4841
• fix(rivetkit): remove requirement for token #4839 : 1 other dependent PR (#4840 )
• fix(pegboard-envoy): allow sqlite requests across lifecycle states #4838
• fix(pegboard): route scoped actor key reads by runner dc #4837
• fix(sqlite-storage): let sqlite open take over stale owners #4834
• fix(engine-tests): parallelize multi-DC startup + enable 6 multi-DC tests #4833
• fix(api): honor cursor in actor_ids list path #4832
• fix(api): silently filter invalid IDs from actor_ids query instead of 400 #4831
• fix(api-peer): make actors_delete idempotent for already-destroyed actors #4830
• fix(pegboard): use Iterator streaming mode in list_names so limit param is honored #4829
• chore(engine-tests): convert envoy tests to Sleep crash policy + triage ignored #4828
• feat(engine-tests): wire envoy actor names through prepopulate_actor_names #4827
• chore(depot): fault injection tests #4868
• feat(sqlite): pitr & forking #4859 : 1 other dependent PR (#4863 )
• chore(sqlite): stateless storage refactor #4856
• main

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[claude]

PR 4896 Review - test(serverless): avoid pinning header validation order

Note: This PR is currently in DRAFT status.

Overview

This PR fixes two related issues: the Rust fallback logic for the deprecated x-rivet-runner-name header was producing a misleading error message when neither header was present, and the test was brittle because it pinned a specific header validation order.

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Rust change (rivetkit-core/src/serverless.rs)

Root cause fixed: The old chain used required_header().or_else(|_| required_header()), which meant when neither header was present, the error came from the fallback call and said "x-rivet-runner-name header is required" instead of the canonical "x-rivet-pool-name header is required". The new code always surfaces the canonical name. Correct fix.

Suggestion - simplify to idiomatic Option::or_else: The match block can be replaced with an optional_header().or_else().ok_or_else() chain. This avoids explicit match arms and is more idiomatic Rust for "try A, fall back to B, error if neither."

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Test change (tests/driver/serverless-handler.test.ts)

Indentation issue: The closing }); for toMatchObject and the subsequent expect call are both indented one level too deep, at the object-content level rather than the call level. This is syntactically valid but visually implies the second expect is nested inside the first. Consider re-indenting for clarity.

Optional chaining on a required field: body.metadata?.reason uses ?. on metadata, which should always be present in an invalid_request response. If metadata is absent, expect(undefined).toMatch(regex) fails with "received value must be a string" rather than a clear missing-field error. Prefer body.metadata.reason.

Regex scope is appropriate: Matching any of the three possible required header names avoids pinning to a specific validation order, which is exactly the goal of this PR.

---

Summary

Item	Severity
Rust: simplify match to or_else chain	Minor (style)
Test: }); indented at wrong level	Minor (formatting)
Test: ?. on always-present metadata field	Minor

The core logic fix is correct. The suggestions above are minor style and quality improvements.