perf(start): compact deferred hydration private state by Sheraff · Pull Request #7980 · TanStack/router

Sheraff · 2026-08-06T05:12:30Z

Summary

shorten descriptive, module-private prefetch-controller keys in Solid's generic hydrator
replace two one-field closure state wrappers with named locals while preserving synchronous-cleanup behavior
store private visible-observer registry entries as labeled tuples, destructured immediately at use sites
add focused lifecycle coverage for synchronous completion, races, cleanup-once behavior, observer sharing, teardown, and recreation

Public APIs and declaration-facing types are unchanged. The controller keys are Solid-only; the representation changes in Start client core retain the same React and Solid behavior.

Bundle impact

Scenario	Raw	Initial gzip	Gzip	Brotli
`solid-start.deferred-hydration`	-361 B	0 B	-55 B	-119 B

The other 16 bundle scenarios are byte-identical. Each production hunk independently improves raw and gzip size; the composed result was remeasured in the full matrix.

Validation

Start client core: 86 unit tests passed; type suite passed on TS 5.6 through 7.0; ESLint has 0 errors
Solid Start client: 8 unit tests passed; type suite passed on TS 5.6 through 7.0; ESLint passed
deferred-hydration e2e: 45 tests passed across Vite SSR, Rsbuild SSR, and Vite
full 17-scenario bundle matrix passed
five independent review passes approved semantics, observer lifecycle, attribution, publishability, and maintainability

Full attribution and validation details are in RESULT-optimization-solid-hydration-private-state.md.

Summary by CodeRabbit

Bug Fixes
- Improved hydration prefetch handling when operations complete immediately or are interrupted.
- Prevented hydration strategies from starting after cancellation.
- Improved cleanup reliability to avoid repeated or incomplete resource disposal.
- Preserved consistent visible-content hydration behavior when multiple elements are observed or cleaned up.
Tests
- Added coverage for hydration timing, cancellation, cleanup, visibility tracking, and observer lifecycle scenarios.

coderabbitai · 2026-08-06T05:12:40Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 2c0a5b27-bb9e-48a3-b855-7589da7f083e

📥 Commits

Reviewing files that changed from the base of the PR and between 222834d and 6985f84.

📒 Files selected for processing (1)

.changeset/shaky-berries-admire.md

📝 Walkthrough

Walkthrough

The changes update hydration prefetch cleanup handling, refactor visible observer registry entries into tuples, rename Solid hydration controller fields, and add tests for synchronous completion, races, aborts, observer sharing, and cleanup.

Changes

Hydration prefetch maintenance

Layer / File(s)	Summary
Prefetch settlement and cleanup `packages/start-client-core/src/hydration/runtime.ts`, `packages/start-client-core/tests/hydration-runtime.test.ts`, `.changeset/shaky-berries-admire.md`	The runtime stores disposal state directly, runs cleanup after synchronous completion, ignores repeated completion, and handles abort races and already-aborted signals. Tests cover these behaviors. The changeset records patch releases for both affected packages.
Visible observer registry `packages/start-client-core/src/hydration/visible.ts`, `packages/start-client-core/tests/hydration-visible.test.ts`	Visible observer entries use `[observer, elements]` tuples. Tests cover shared observers, callback removal, disconnection, and observer replacement.
Solid hydration controller alignment `packages/solid-start-client/src/GenericHydrate.tsx`	Hydration-prefetch logic uses the renamed `abort`, `listeners`, `requested`, and `resolvePending` controller fields.

Estimated code review effort: 3 (Moderate) | ~20 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: reducing private deferred-hydration state.
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch codex/solid-hydration-private-state

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nx-cloud · 2026-08-06T05:12:59Z

View your CI Pipeline Execution ↗ for commit 40f9baa

Command	Status	Duration	Result
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`nx run-many --target=build --exclude=examples/*...`	✅ Succeeded	1m 56s	View ↗

☁️ Nx Cloud last updated this comment at 2026-08-07 14:08:19 UTC

github-actions · 2026-08-06T05:13:49Z

🚀 Changeset Version Preview

2 package(s) bumped directly, 12 bumped as dependents.

🟩 Patch bumps

Package	Version	Reason
`@tanstack/solid-start-client`	1.168.20 → 1.168.21	Changeset
`@tanstack/start-client-core`	1.170.18 → 1.170.19	Changeset
`@tanstack/react-start`	1.168.39 → 1.168.40	Dependent
`@tanstack/react-start-client`	1.168.20 → 1.168.21	Dependent
`@tanstack/react-start-rsc`	0.1.38 → 0.1.39	Dependent
`@tanstack/react-start-server`	1.167.27 → 1.167.28	Dependent
`@tanstack/solid-start`	1.168.38 → 1.168.39	Dependent
`@tanstack/solid-start-server`	1.167.27 → 1.167.28	Dependent
`@tanstack/start-plugin-core`	1.171.30 → 1.171.31	Dependent
`@tanstack/start-server-core`	1.169.22 → 1.169.23	Dependent
`@tanstack/start-static-server-functions`	1.167.23 → 1.167.24	Dependent
`@tanstack/vue-start`	1.168.37 → 1.168.38	Dependent
`@tanstack/vue-start-client`	1.167.23 → 1.167.24	Dependent
`@tanstack/vue-start-server`	1.167.27 → 1.167.28	Dependent

github-actions · 2026-08-06T05:15:46Z

Bundle Size Benchmarks

Commit: a980dd360583
Measured at: 2026-08-07T13:51:36.652Z
Baseline source: history:995bd97a9f6c
Dashboard: bundle-size history

The following scenarios have bundle-size changes compared with the baseline:

Scenario	Current (gzip)	Delta vs baseline	Initial gzip	Raw	Brotli	Trend
`react-start.minimal`	100.39 KiB	-8 B (-0.01%)	100.25 KiB	310.86 KiB	87.16 KiB	█▂▂▂▂▁▁▁▁▁▁
`react-start.deferred-hydration`	101.13 KiB	-9 B (-0.01%)	100.28 KiB	312.23 KiB	87.87 KiB	█▂▂▂▂▁▁▁▁▁▁
`react-start.full`	103.75 KiB	-3 B (-0.00%)	103.61 KiB	320.81 KiB	90.16 KiB	█▂▂▂▂▁▁▁▁▁▁
`react-start.rsbuild.minimal`	99.98 KiB	-8 B (-0.01%)	99.81 KiB	315.35 KiB	86.25 KiB	▁████▃▃▃▄▄▄
`react-start.rsbuild.minimal-iife`	100.39 KiB	-9 B (-0.01%)	100.22 KiB	316.28 KiB	86.60 KiB	▁████▃▃▃▄▄▄
`react-start.rsbuild.full`	103.28 KiB	-11 B (-0.01%)	103.11 KiB	325.44 KiB	88.92 KiB	▁██▇█▃▃▃▄▄▃
`solid-start.minimal`	47.96 KiB	-5 B (-0.01%)	47.83 KiB	140.63 KiB	42.69 KiB	█▂▂▂▂▁▁▁▁▁▁
`solid-start.deferred-hydration`	51.17 KiB	-65 B (-0.12%)	47.89 KiB	148.31 KiB	45.63 KiB	█▂▂▂▂▁▁▁▁▁▁▁
`solid-start.full`	53.23 KiB	-8 B (-0.01%)	53.11 KiB	156.35 KiB	47.32 KiB	█▂▂▂▂▁▁▁▁▁▁
`vue-start.minimal`	68.64 KiB	-5 B (-0.01%)	68.51 KiB	193.40 KiB	61.10 KiB	█▃▃▂▂▁▁▁▁▁▁
`vue-start.full`	72.65 KiB	-4 B (-0.01%)	72.52 KiB	205.90 KiB	64.57 KiB	█▂▂▂▂▁▁▁▁▁▁

Current gzip tracks all emitted client JS chunks. Initial gzip tracks only the entry/import graph. Trend sparkline is historical current gzip ending with this PR measurement; lower is better.

pkg-pr-new · 2026-08-06T05:17:48Z

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commit: 2dbe700

codspeed-hq · 2026-08-06T05:28:12Z

Merging this PR will degrade performance by 1.89%

⚠️

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

⚡ 4 improved benchmarks
❌ 7 (👁 1) regressed benchmarks
✅ 169 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
❌	Memory	`mem client unique-location-churn (solid)`	341.4 KB	563.4 KB	-39.4%
❌	Memory	`mem server serialization-payload (react)`	3.2 MB	3.5 MB	-7.31%
❌	Memory	`mem server error-paths redirect (react)`	208.4 KB	223.1 KB	-6.6%
❌	Memory	`mem client preload-churn (vue)`	737 KB	769.2 KB	-4.19%
❌	Memory	`mem server error-paths not-found (react)`	250.3 KB	261 KB	-4.1%
❌	Memory	`mem client loader-data-retention (solid)`	148.5 KB	154.4 KB	-3.8%
⚡	Memory	`mem server error-paths redirect (vue)`	500.2 KB	294 KB	+70.15%
⚡	Memory	`mem client navigation-churn (vue)`	1.3 MB	1.2 MB	+5.1%
⚡	Simulation	`ssr control-flow unmatched 404 (react)`	66.1 ms	64 ms	+3.28%
⚡	Memory	`mem server error-paths not-found (vue)`	329.6 KB	319.4 KB	+3.21%
👁	Simulation	`ssr request loop (solid)`	145.5 ms	158.7 ms	-8.31%

Tip

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

_{Comparing codex/solid-hydration-private-state (2dbe700) with main (2fbc99f)}

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.

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

Sheraff added 5 commits August 6, 2026 06:55

perf(solid-start): shorten private prefetch state
5c5b344

perf(start): use locals for hydration wait state
f45fa46

perf(start): compact visible observer registry entries
c6ffcdd

test(start): cover hydration private-state lifecycles
33f709a

docs: record solid hydration bundle result
5ba6b5f

github-actionsBot added package: solid-start-client package: start-client-core labels Aug 6, 2026

Delete RESULT-optimization-solid-hydration-private-state.md
222834d

Sheraff marked this pull request as ready for review August 6, 2026 07:28

Sheraff added 4 commits August 6, 2026 12:49

changeset
6985f84

Merge branch 'main' into codex/solid-hydration-private-state
9c44de1

Merge branch 'main' into codex/solid-hydration-private-state
d91289e

Merge branch 'main' into codex/solid-hydration-private-state
40f9baa

nx-cloudBot reviewed Aug 7, 2026
View reviewed changes

ci: Version Packages (#7993) [Self-Healing CI Rerun]
2dbe700

Sheraff merged commit 6bede65 into mainAug 7, 2026
25 of 26 checks passed

Sheraff deleted the codex/solid-hydration-private-state branch August 7, 2026 15:30

github-actionsBot mentioned this pull request Aug 7, 2026
ci: Version Packages #7994
Merged

brenelz mentioned this pull request Aug 13, 2026
Merge main into upgrade-solidjs-rc-0 #8059
Merged

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perf(start): compact deferred hydration private state - #7980

perf(start): compact deferred hydration private state#7980
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Merging this PR will degrade performance by 1.89%

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