perf: skip unused Start request setup by schiller-manuel · Pull Request #8451 · TanStack/router

schiller-manuel · 2026-09-16T18:26:52Z

🎯 Changes

Stacked on #8444.

Skip request setup when its corresponding Start feature is unused:

Render directly when matched routes have no middleware or handler to execute, preserving HEAD fallback behavior.
Return cached manifest promises directly when asset options are static.
Skip empty middleware flattening and deduplication sets, and avoid awaiting absent Start configuration.
Reuse the parsed request origin and serialization adapters.
Use the router's decoded pathname for server route handlers and route middleware.

Validation: affected unit, type, and lint checks across 16 projects; server-route and global server-function middleware Chromium suites (13 tests). All 18 client bundle scenarios have unchanged raw, gzip, initial-gzip, and Brotli sizes.

✅ Checklist

I have followed the steps in the Contributing guide.
I have tested code changes locally with the relevant test commands, or tests do not apply to this pull request.
I fully understand the code in this pull request, including any code generated with AI assistance.

🚀 Release Impact

This change affects published code, and I have generated a changeset.
This change is docs/CI/dev-only (no release).

Summary by CodeRabbit

Bug Fixes
- Improved handling of requests without configured Start instances or middleware.
- Corrected server route handling for encoded and decoded pathnames.
- Ensured request origins are derived consistently from the request URL.
- Preserved middleware execution context and serialization adapter ordering across requests.
- Improved cached manifest reuse when asset transformation is not configured.
Tests
- Expanded coverage for server rendering, middleware behavior, request origins, path parameters, serialization adapters, and manifest caching.

coderabbitai · 2026-09-16T18:27:00Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Advanced

Run ID: 6d9df1f4-7029-4788-8c4c-4afc7dd0ff19

📥 Commits

Reviewing files that changed from the base of the PR and between 92dfe48 and 9dffae9.

📒 Files selected for processing (7)

.changeset/honest-walls-attack.md
packages/start-client-core/src/createServerFn.ts
packages/start-server-core/src/createStartHandler.ts
packages/start-server-core/src/finalManifest.ts
packages/start-server-core/tests/createStartHandler.test.ts
packages/start-server-core/tests/finalManifest.test.ts
packages/start-storage-context/src/async-local-storage.ts

🚧 Files skipped from review as they are similar to previous changes (2)

.changeset/honest-walls-attack.md
packages/start-client-core/src/createServerFn.ts

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📝 Walkthrough

Walkthrough

The changes update server request routing, middleware execution, serialization adapter handling, request origin resolution, decoded pathname handling, and final manifest caching. Tests cover these behaviors, and a changeset records patch releases.

Changes

Server runtime fixes

Layer / File(s)	Summary
Request routing and middleware execution `packages/start-storage-context/src/async-local-storage.ts`, `packages/start-client-core/src/createServerFn.ts`, `packages/start-server-core/src/createStartHandler.ts`, `packages/start-server-core/tests/createStartHandler.test.ts`, `.changeset/honest-walls-attack.md`	Start configuration and middleware state can be absent. Empty middleware chains are skipped. Router origins use the request URL. Serialization adapters remain ordered and request-isolated. Server handlers use decoded route pathnames while preserving encoded pathname data.
Final manifest cache resolution `packages/start-server-core/src/finalManifest.ts`, `packages/start-server-core/tests/finalManifest.test.ts`	Cached manifests are returned directly when asset transformation is not configured and the requested inline-CSS mode matches a cached entry. Tests cover cache reuse, overrides, uncached loading, and request-dependent CSS settings.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Refactor

Suggested reviewers: sheraff

Sequence Diagram(s)

sequenceDiagram
  participant Request
  participant createStartHandler
  participant Router
  participant executeRouter
  Request->>createStartHandler: request URL and request context
  createStartHandler->>Router: configure origin and serialization adapters
  Router->>createStartHandler: matched routes and latest pathname
  createStartHandler->>executeRouter: execute route without empty middleware chain
  executeRouter-->>Request: server route response

Merge Risk: ⚪ Minimal · up to 9dffa

The optimized request and manifest paths preserve their relevant middleware and cache contracts, with no unresolved merge-blocking issue identified.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 6 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly identifies the primary change: skipping unused Start request setup. It is concise and relevant to the performance optimizations in the pull request.
Description check	✅ Passed	The description follows the required template. It explains the changes and motivation, confirms testing and contributor-guide compliance, and records the published-code impact with a changeset.

Full details: Docstring Coverage

Explanation

Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 6 files. (1 skipped: 1 unsupported.)

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Commit unit tests in branch codex/trim-unused-start-request-work

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nx-cloud · 2026-09-16T18:27:28Z

View your CI Pipeline Execution ↗ for commit 9dffae9

Command	Status	Duration	Result
`nx run-many --target=build --exclude=examples/*...`	✅ Succeeded	1m 27s	View ↗

☁️ Nx Cloud last updated this comment at 2026-09-16 21:24:40 UTC

github-actions · 2026-09-16T18:28:25Z

🚀 Changeset Version Preview

4 package(s) bumped directly, 19 bumped as dependents.

🟩 Patch bumps

Package	Version	Reason
`@tanstack/router-core`	1.171.31 → 1.171.32	Changeset
`@tanstack/start-plugin-core`	1.171.45 → 1.171.46	Changeset
`@tanstack/start-server-core`	1.169.36 → 1.169.37	Changeset
`@tanstack/start-storage-context`	1.167.33 → 1.167.34	Changeset
`@tanstack/react-router`	1.170.37 → 1.170.38	Dependent
`@tanstack/react-start`	1.168.55 → 1.168.56	Dependent
`@tanstack/react-start-client`	1.168.35 → 1.168.36	Dependent
`@tanstack/react-start-rsc`	0.1.54 → 0.1.55	Dependent
`@tanstack/react-start-server`	1.167.42 → 1.167.43	Dependent
`@tanstack/router-cli`	1.167.37 → 1.167.38	Dependent
`@tanstack/router-generator`	1.167.37 → 1.167.38	Dependent
`@tanstack/router-plugin`	1.168.39 → 1.168.40	Dependent
`@tanstack/router-vite-plugin`	1.167.39 → 1.167.40	Dependent
`@tanstack/solid-router`	1.170.35 → 1.170.36	Dependent
`@tanstack/solid-start`	1.168.53 → 1.168.54	Dependent
`@tanstack/solid-start-client`	1.168.34 → 1.168.35	Dependent
`@tanstack/solid-start-server`	1.167.41 → 1.167.42	Dependent
`@tanstack/start-client-core`	1.170.31 → 1.170.32	Dependent
`@tanstack/start-static-server-functions`	1.167.36 → 1.167.37	Dependent
`@tanstack/vue-router`	1.170.34 → 1.170.35	Dependent
`@tanstack/vue-start`	1.168.52 → 1.168.53	Dependent
`@tanstack/vue-start-client`	1.167.37 → 1.167.38	Dependent
`@tanstack/vue-start-server`	1.167.41 → 1.167.42	Dependent

pkg-pr-new · 2026-09-16T18:31:54Z

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commit: 9dffae9

github-actions · 2026-09-16T18:33:58Z

Bundle Size Benchmarks

This pull request does not affect bundle size in any measured scenario.

codspeed · 2026-09-16T18:42:46Z

Merging this PR will degrade performance by 0.09%

⚠️

Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
❌ 1 regressed benchmark
✅ 187 untouched benchmarks
⏩ 3 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
❌	Memory	`mem client unique-location-churn (vue)`	2 MB	2.1 MB	-4.27%
⚡	Simulation	`ssr rewrite localized (react)`	182.4 ms	174.9 ms	+4.27%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

_{Comparing codex/trim-unused-start-request-work (9dffae9) with codex/skip-unused-start-routing (6604453)}

3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

nx-cloud

Nx Cloud has identified a flaky task in your failed CI:

🔂 Since the failure was identified as flaky, we triggered a CI rerun by adding an empty commit to this branch.

View detailed reasoning in Nx Cloud ↗

_{🎓 Learn more about Self-Healing CI on nx.dev}

github-actions Bot added package: start-server-core package: start-client-core package: start-storage-context labels Sep 16, 2026

schiller-manuel mentioned this pull request Sep 16, 2026

fix: redirect to canonical search URLs before rendering #8452

Open

5 tasks

schiller-manuel added this pull request to stack #8445 September 16, 2026 18:28

schiller-manuel force-pushed the codex/trim-unused-start-request-work branch from d3c2816 to 001baa4 Compare September 16, 2026 18:45

nx-cloud Bot reviewed Sep 16, 2026

View reviewed changes

schiller-manuel and others added 2 commits September 16, 2026 23:10

perf: skip unused Start request setup

c9cad2e

perf: skip unused Start request setup [Self-Healing CI Rerun]

9dffae9

schiller-manuel force-pushed the codex/trim-unused-start-request-work branch from 92dfe48 to 9dffae9 Compare September 16, 2026 21:11

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perf: skip unused Start request setup - #8451

perf: skip unused Start request setup#8451
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