fix: disabled topLevelVar by schiller-manuel · Pull Request #7293 · TanStack/router

schiller-manuel · 2026-04-29T19:50:13Z

this will cause isServer not to be transpiled to var and thus rspack can properly DCE

Summary by CodeRabbit

Bug Fixes
- Fixed build output configuration to properly preserve critical exports during dead-code elimination, ensuring correct behavior with rspack bundler.

this will cause isServer not to be transpiled to `var` and thus rspack can properly DCE

nx-cloud · 2026-04-29T19:50:49Z

View your CI Pipeline Execution ↗ for commit 9608c2c

Command	Status	Duration	Result
`nx affected --targets=test:eslint,test:unit,tes...`	✅ Succeeded	8m 20s	View ↗
`nx run-many --target=build --exclude=examples/*...`	✅ Succeeded	1m 55s	View ↗

☁️ Nx Cloud last updated this comment at 2026-04-29 20:02:46 UTC

github-actions · 2026-04-29T19:51:05Z

🚀 Changeset Version Preview

1 package(s) bumped directly, 22 bumped as dependents.

🟩 Patch bumps

Package	Version	Reason
`@tanstack/router-core`	1.168.17 → 1.168.18	Changeset
`@tanstack/react-router`	1.168.25 → 1.168.26	Dependent
`@tanstack/react-start`	1.167.51 → 1.167.52	Dependent
`@tanstack/react-start-client`	1.166.43 → 1.166.44	Dependent
`@tanstack/react-start-rsc`	0.0.30 → 0.0.31	Dependent
`@tanstack/react-start-server`	1.166.44 → 1.166.45	Dependent
`@tanstack/router-cli`	1.166.37 → 1.166.38	Dependent
`@tanstack/router-generator`	1.166.36 → 1.166.37	Dependent
`@tanstack/router-plugin`	1.167.28 → 1.167.29	Dependent
`@tanstack/router-vite-plugin`	1.166.43 → 1.166.44	Dependent
`@tanstack/solid-router`	1.168.25 → 1.168.26	Dependent
`@tanstack/solid-start`	1.167.48 → 1.167.49	Dependent
`@tanstack/solid-start-client`	1.166.42 → 1.166.43	Dependent
`@tanstack/solid-start-server`	1.166.43 → 1.166.44	Dependent
`@tanstack/start-client-core`	1.167.20 → 1.167.21	Dependent
`@tanstack/start-plugin-core`	1.169.6 → 1.169.7	Dependent
`@tanstack/start-server-core`	1.167.22 → 1.167.23	Dependent
`@tanstack/start-static-server-functions`	1.166.36 → 1.166.37	Dependent
`@tanstack/start-storage-context`	1.166.31 → 1.166.32	Dependent
`@tanstack/vue-router`	1.168.21 → 1.168.22	Dependent
`@tanstack/vue-start`	1.167.44 → 1.167.45	Dependent
`@tanstack/vue-start-client`	1.166.38 → 1.166.39	Dependent
`@tanstack/vue-start-server`	1.166.39 → 1.166.40	Dependent

coderabbitai · 2026-04-29T19:52:37Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: dcc7d638-5314-48f4-adcf-eaec29b610a4

📥 Commits

Reviewing files that changed from the base of the PR and between d406d1a and 5b47836.

📒 Files selected for processing (2)

.changeset/slow-seahorses-grab.md
packages/router-core/vite.config.ts

📝 Walkthrough

Walkthrough

This PR adds configuration changes for the router-core package to preserve isServer exports during build by disabling the topLevelVar transformation. A Changeset entry documents this patch-level fix intended to enable rspack dead-code elimination.

Changes

Cohort / File(s)	Summary
Build Configuration & Metadata `.changeset/slow-seahorses-grab.md`, `packages/router-core/vite.config.ts`	Added Changeset documenting patch-level fix for `isServer` export preservation, and updated Vite configuration to disable `topLevelVar` transformation to support rspack dead-code elimination.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

🐰 A changeset hops in with cheer,
Vite configs crystal and clear,
Top-level vars? We bid adieu,
Dead code vanishes on cue! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix: disabled topLevelVar' directly corresponds to the main change in the PR, which disables the topLevelVar behavior in the Vite configuration to enable proper dead code elimination.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

Create stacked PR
Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch topLevelVar

_{Review rate limit: 4/5 reviews remaining, refill in 12 minutes.}

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

github-actions · 2026-04-29T19:55:42Z

Bundle Size Benchmarks

Commit: d406d1a45076
Measured at: 2026-04-29T19:55:00.693Z
Baseline source: history:d6decca41807
Dashboard: bundle-size history

Scenario	Current (gzip)	Delta vs baseline	Raw	Brotli	Trend
`react-router.minimal`	87.30 KiB	0 B (0.00%)	274.68 KiB	75.83 KiB	████████▁▁▁
`react-router.full`	90.80 KiB	0 B (0.00%)	286.19 KiB	79.00 KiB	▁▁▁▁▁▁▁▁███
`solid-router.minimal`	35.55 KiB	0 B (0.00%)	106.95 KiB	31.97 KiB	▁▁▁▁████▁▁▁
`solid-router.full`	40.28 KiB	0 B (0.00%)	121.16 KiB	36.16 KiB	▁▁▁▁▄███▄▄▄
`vue-router.minimal`	53.30 KiB	0 B (0.00%)	152.09 KiB	47.88 KiB	████████▁▁▁
`vue-router.full`	58.44 KiB	0 B (0.00%)	168.27 KiB	52.33 KiB	▁▁▁▁▁▁▁▁███
`react-start.minimal`	101.92 KiB	0 B (0.00%)	322.84 KiB	88.06 KiB	▁▁▁▁▁▁▁▁███
`react-start.full`	105.34 KiB	0 B (0.00%)	333.17 KiB	90.98 KiB	████████▁▁▁
`react-start.rsbuild.minimal`	99.53 KiB	-1.92 KiB (-1.90%)	317.16 KiB	85.62 KiB	███████████▁
`react-start.rsbuild.full`	102.84 KiB	-1.91 KiB (-1.83%)	327.59 KiB	88.41 KiB	███████████▁
`solid-start.minimal`	49.55 KiB	0 B (0.00%)	152.77 KiB	43.68 KiB	▁▁▁▁████▂▂▂
`solid-start.full`	55.33 KiB	0 B (0.00%)	169.68 KiB	48.71 KiB	▁▁▁▁▃███▅▅▅

Trend sparkline is historical gzip bytes ending with this PR measurement; lower is better.

pkg-pr-new · 2026-04-29T19:57:19Z

More templates

@tanstack/arktype-adapter

npm i https://pkg.pr.new/@tanstack/arktype-adapter@7293

@tanstack/eslint-plugin-router

npm i https://pkg.pr.new/@tanstack/eslint-plugin-router@7293

@tanstack/eslint-plugin-start

npm i https://pkg.pr.new/@tanstack/eslint-plugin-start@7293

@tanstack/history

npm i https://pkg.pr.new/@tanstack/history@7293

@tanstack/nitro-v2-vite-plugin

npm i https://pkg.pr.new/@tanstack/nitro-v2-vite-plugin@7293

@tanstack/react-router

npm i https://pkg.pr.new/@tanstack/react-router@7293

@tanstack/react-router-devtools

npm i https://pkg.pr.new/@tanstack/react-router-devtools@7293

@tanstack/react-router-ssr-query

npm i https://pkg.pr.new/@tanstack/react-router-ssr-query@7293

@tanstack/react-start

npm i https://pkg.pr.new/@tanstack/react-start@7293

@tanstack/react-start-client

npm i https://pkg.pr.new/@tanstack/react-start-client@7293

@tanstack/react-start-rsc

npm i https://pkg.pr.new/@tanstack/react-start-rsc@7293

@tanstack/react-start-server

npm i https://pkg.pr.new/@tanstack/react-start-server@7293

@tanstack/router-cli

npm i https://pkg.pr.new/@tanstack/router-cli@7293

@tanstack/router-core

npm i https://pkg.pr.new/@tanstack/router-core@7293

@tanstack/router-devtools

npm i https://pkg.pr.new/@tanstack/router-devtools@7293

@tanstack/router-devtools-core

npm i https://pkg.pr.new/@tanstack/router-devtools-core@7293

@tanstack/router-generator

npm i https://pkg.pr.new/@tanstack/router-generator@7293

@tanstack/router-plugin

npm i https://pkg.pr.new/@tanstack/router-plugin@7293

@tanstack/router-ssr-query-core

npm i https://pkg.pr.new/@tanstack/router-ssr-query-core@7293

@tanstack/router-utils

npm i https://pkg.pr.new/@tanstack/router-utils@7293

@tanstack/router-vite-plugin

npm i https://pkg.pr.new/@tanstack/router-vite-plugin@7293

@tanstack/solid-router

npm i https://pkg.pr.new/@tanstack/solid-router@7293

@tanstack/solid-router-devtools

npm i https://pkg.pr.new/@tanstack/solid-router-devtools@7293

@tanstack/solid-router-ssr-query

npm i https://pkg.pr.new/@tanstack/solid-router-ssr-query@7293

@tanstack/solid-start

npm i https://pkg.pr.new/@tanstack/solid-start@7293

@tanstack/solid-start-client

npm i https://pkg.pr.new/@tanstack/solid-start-client@7293

@tanstack/solid-start-server

npm i https://pkg.pr.new/@tanstack/solid-start-server@7293

@tanstack/start-client-core

npm i https://pkg.pr.new/@tanstack/start-client-core@7293

@tanstack/start-fn-stubs

npm i https://pkg.pr.new/@tanstack/start-fn-stubs@7293

@tanstack/start-plugin-core

npm i https://pkg.pr.new/@tanstack/start-plugin-core@7293

@tanstack/start-server-core

npm i https://pkg.pr.new/@tanstack/start-server-core@7293

@tanstack/start-static-server-functions

npm i https://pkg.pr.new/@tanstack/start-static-server-functions@7293

@tanstack/start-storage-context

npm i https://pkg.pr.new/@tanstack/start-storage-context@7293

@tanstack/valibot-adapter

npm i https://pkg.pr.new/@tanstack/valibot-adapter@7293

@tanstack/virtual-file-routes

npm i https://pkg.pr.new/@tanstack/virtual-file-routes@7293

@tanstack/vue-router

npm i https://pkg.pr.new/@tanstack/vue-router@7293

@tanstack/vue-router-devtools

npm i https://pkg.pr.new/@tanstack/vue-router-devtools@7293

@tanstack/vue-router-ssr-query

npm i https://pkg.pr.new/@tanstack/vue-router-ssr-query@7293

@tanstack/vue-start

npm i https://pkg.pr.new/@tanstack/vue-start@7293

@tanstack/vue-start-client

npm i https://pkg.pr.new/@tanstack/vue-start-client@7293

@tanstack/vue-start-server

npm i https://pkg.pr.new/@tanstack/vue-start-server@7293

@tanstack/zod-adapter

npm i https://pkg.pr.new/@tanstack/zod-adapter@7293

commit: 5b47836

codspeed-hq · 2026-04-29T20:12:35Z

Merging this PR will not alter performance

✅ 5 untouched benchmarks
⏩ 1 skipped benchmark¹

_{Comparing topLevelVar (5b47836) with main (d6decca)²}

1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩
No successful run was found on main (d406d1a) during the generation of this report, so d6decca was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

dsonet · 2026-04-29T20:42:07Z

+  build: {
+    rolldownOptions: {
+      output: {
+        topLevelVar: false,


According to the document here: https://rolldown.rs/reference/OutputOptions.topLevelVar

It is default to ‘false’.

true for rolldown alone, but vite sets it to true by default: https://github.com/vitejs/vite/blob/7c3a61f42da6445904e93f0e29e9a2a838fa684a/packages/vite/src/node/build.ts#L768

fix: disabled topLevelVar

9608c2c

this will cause isServer not to be transpiled to `var` and thus rspack can properly DCE

github-actions Bot added the package: router-core label Apr 29, 2026

ci: apply automated fixes

5b47836

schiller-manuel merged commit b5c4183 into main Apr 29, 2026
17 checks passed

schiller-manuel deleted the topLevelVar branch April 29, 2026 20:15

dsonet reviewed Apr 29, 2026

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

fix: disabled topLevelVar#7293

fix: disabled topLevelVar#7293
schiller-manuel merged 2 commits intomainfrom
topLevelVar

schiller-manuel commented Apr 29, 2026 •

edited by coderabbitai Bot

Loading

Uh oh!

nx-cloud Bot commented Apr 29, 2026 •

edited

Loading

Uh oh!

github-actions Bot commented Apr 29, 2026 •

edited

Loading

Uh oh!

coderabbitai Bot commented Apr 29, 2026 •

edited

Loading

Walkthrough

Changes

Estimated code review effort

Poem

Uh oh!

github-actions Bot commented Apr 29, 2026

Uh oh!

pkg-pr-new Bot commented Apr 29, 2026

Uh oh!

codspeed-hq Bot commented Apr 29, 2026

Uh oh!

Uh oh!

dsonet Apr 29, 2026

Uh oh!

schiller-manuel Apr 29, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Uh oh!

Conversation

schiller-manuel commented Apr 29, 2026 • edited by coderabbitai Bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary by CodeRabbit

Uh oh!

nx-cloud Bot commented Apr 29, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions Bot commented Apr 29, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

🚀 Changeset Version Preview

🟩 Patch bumps

Uh oh!

coderabbitai Bot commented Apr 29, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Walkthrough

Changes

Estimated code review effort

Poem

Uh oh!

github-actions Bot commented Apr 29, 2026

Bundle Size Benchmarks

Uh oh!

pkg-pr-new Bot commented Apr 29, 2026

Uh oh!

codspeed-hq Bot commented Apr 29, 2026

Merging this PR will not alter performance

Footnotes

Uh oh!

Uh oh!

dsonet Apr 29, 2026

Choose a reason for hiding this comment

Uh oh!

schiller-manuel Apr 29, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

schiller-manuel commented Apr 29, 2026 •

edited by coderabbitai Bot

Loading

nx-cloud Bot commented Apr 29, 2026 •

edited

Loading

github-actions Bot commented Apr 29, 2026 •

edited

Loading

coderabbitai Bot commented Apr 29, 2026 •

edited

Loading