fix(solid-virtual): preserve measurements on option updates by Hona · Pull Request #1203 · TanStack/virtual

Hona · 2026-06-16T11:19:54Z

Summary

replace the Solid adapter's full measure() invalidation on reactive option updates with the normal virtualizer update lifecycle
publish virtual items and total size through Solid without clearing measured item sizes
add the Solid adapter's first library regression test

This aligns Solid with the lifecycle used by the other adapters:

React calls setOptions() during render and _willUpdate() after commit
Vue calls setOptions(), _willUpdate(), then triggerRef()
Svelte calls setOptions(), _willUpdate(), then explicitly publishes its store
Solid now calls setOptions(), _willUpdate(), then explicitly publishes its virtual items and total size

The framework publication mechanism differs, but reactive option updates no longer trigger a full measurement invalidation only in Solid.

OpenCode hit this while migrating its long desktop chat timeline from Virtua to TanStack Virtual. Streaming messages, prepended history, and asynchronously resizing tool output require retained visible rows to preserve their measurements; clearing them on a reactive count update caused temporary estimated geometry and visible movement.

The regression test measures a row at 100px, reactively increases count, and verifies the measurement and resulting total size remain intact.

Fixes #1197

Downstream context: anomalyco/opencode#32331
Downstream patch: https://github.com/anomalyco/opencode/blob/refactor/tanstack-virtual-session/patches/%40tanstack%252Fsolid-virtual%403.13.28.patch

Verification

pnpm --filter @tanstack/solid-virtual test:lib --run
pnpm --filter @tanstack/solid-virtual test:types
pnpm --filter @tanstack/solid-virtual test:eslint
pnpm --filter @tanstack/solid-virtual build
Prettier check for changed files

Summary by CodeRabbit

Bug Fixes
- Preserved measured virtualized item sizes when reactive virtualizer settings change.
- Improved updates so virtualized item measurements and total size stay in sync after option changes.
Tests
- Added coverage for reactive updates to confirm previously measured sizes are retained.

coderabbitai · 2026-06-16T11:20:08Z

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: b93b3e32-99d2-4b7b-a685-06fe5b37a2e6

📥 Commits

Reviewing files that changed from the base of the PR and between 2346cc5 and 3d8b455.

📒 Files selected for processing (1)

packages/solid-virtual/package.json

✅ Files skipped from review due to trivial changes (1)

packages/solid-virtual/package.json

📝 Walkthrough

Walkthrough

createVirtualizerBase now refreshes Solid state with _willUpdate(), reconcile, and totalSize updates instead of calling measure(). The PR also adds a regression test, test scripts, and a patch changeset.

Changes

Preserve measured sizes on reactive option update

Layer / File(s)	Summary
onChange handler fix + test wiring `packages/solid-virtual/src/index.tsx`, `packages/solid-virtual/package.json`, `packages/solid-virtual/tests/index.test.ts`	Replaces `virtualizer.measure()` with `instance._willUpdate()`, `setVirtualItems(reconcile(instance.getVirtualItems(), { key: 'index' }))`, and `setTotalSize(instance.getTotalSize())` in the `onChange` handler. Adds `test:lib` and `test:lib:dev` npm scripts. A Vitest regression test verifies measured sizes persist after a reactive `count` update.
Patch changeset `.changeset/quiet-cats-preserve.md`	Adds a Changesets entry for `@tanstack/solid-virtual` at `patch` level, noting preserved measured item sizes on reactive option changes.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

TanStack/virtual#1183 — Both changes preserve measured item sizes by avoiding forced re-measurement and reusing cached measurements.

Suggested reviewers: piecyk

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the change and verification, but it does not follow the required template sections.	Add the required ## 🎯 Changes, ## ✅ Checklist, and ## 🚀 Release Impact sections, and fill in the checklist items.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the core fix: preserving measurements when Solid virtualizer options update.
Linked Issues check	✅ Passed	The changes match `#1197` by replacing measure() invalidation with lifecycle updates and explicit Solid state publication.
Out of Scope Changes check	✅ Passed	The added test script and changeset support the fix and do not appear unrelated to the PR objective.

✨ Finishing Touches

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Copilot

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR updates the Solid Virtualizer integration to preserve previously measured item sizes when reactive virtualizer options (e.g., count) change, and adds coverage plus tooling to validate the behavior.

Changes:

Replace the reactive-update path to avoid re-measuring in a way that drops cached item sizes.
Add a Vitest test verifying measured sizes persist across reactive option updates.
Add package scripts to run the library test suite and include a changeset for a patch release.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
packages/solid-virtual/src/index.tsx	Changes update flow to preserve measured size cache across reactive option changes.
packages/solid-virtual/tests/index.test.ts	Adds a regression test for preserving measured sizes when reactive options change.
packages/solid-virtual/package.json	Adds Vitest scripts for running the new test suite.
.changeset/quiet-cats-preserve.md	Documents the patch-level behavior change for release notes.

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nx-cloud · 2026-07-01T07:31:30Z

View your CI Pipeline Execution ↗ for commit 3d8b455

Command	Status	Duration	Result
`nx affected --targets=test:sherif,test:knip,tes...`	✅ Succeeded	16s	View ↗
`nx run-many --target=build --exclude=examples/**`	✅ Succeeded	19s	View ↗

☁️ Nx Cloud last updated this comment at 2026-07-01 07:31:44 UTC

pkg-pr-new · 2026-07-01T07:31:54Z

More templates

@tanstack/angular-virtual

npm i https://pkg.pr.new/@tanstack/angular-virtual@1203

@tanstack/lit-virtual

npm i https://pkg.pr.new/@tanstack/lit-virtual@1203

@tanstack/marko-virtual

npm i https://pkg.pr.new/@tanstack/marko-virtual@1203

@tanstack/react-virtual

npm i https://pkg.pr.new/@tanstack/react-virtual@1203

@tanstack/solid-virtual

npm i https://pkg.pr.new/@tanstack/solid-virtual@1203

@tanstack/svelte-virtual

npm i https://pkg.pr.new/@tanstack/svelte-virtual@1203

@tanstack/virtual-core

npm i https://pkg.pr.new/@tanstack/virtual-core@1203

@tanstack/vue-virtual

npm i https://pkg.pr.new/@tanstack/vue-virtual@1203

commit: 3d8b455

fix(solid-virtual): preserve measurements on option updates

2346cc5

Copilot AI review requested due to automatic review settings June 16, 2026 11:19

Copilot AI reviewed Jun 16, 2026

View reviewed changes

Comment thread packages/solid-virtual/src/index.tsx

Comment thread packages/solid-virtual/package.json

Comment thread packages/solid-virtual/tests/index.test.ts

Comment thread packages/solid-virtual/tests/index.test.ts

Merge branch 'main' into fix/solid-preserve-measurements

3d8b455

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fix(solid-virtual): preserve measurements on option updates#1203

fix(solid-virtual): preserve measurements on option updates#1203
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