[kianbazza]

Summary

Bun 1.4.3 ships bun check, a type checker ported from TypeScript 7.0.2 (the version the repo pins). It reads the same tsconfig.json and reports the same errors as tsc. This moves the repo and CI to 1.4.3 and swaps the type-check scripts over.

 .prototools                  bun = "1.3.11"  →  "1.4.3"
 package.json                 "packageManager": "bun@1.3.11"  →  "bun@1.4.3"
 .github/workflows/*.yml      bun-version: 1.3.11  →  bun-version-file: package.json
 */package.json               "type-check": "tsc --noEmit"  →  "bun check"
 apps/web/package.json        "type-check": "tsc --noEmit"  →  "bun --check"

apps/web has its own check script (Biome), and bun check runs a package's check script when one exists. bun --check always means the type checker. typescript stays installed for editors and the .d.ts builds.

Evidence

Same result as tsc in every package, measured on canary before the switch (wall time):

Package	tsc --noEmit	bun check
apps/playground-nextjs	0.20 s	0.04 s
apps/web	1.10 s cold, 0.30 s warm	0.34 s
packages/filters	0.29 s	0.07 s
packages/react	0.47 s	0.12 s
tooling/lint (TS 5.9)	0.45 s	0.04 s

apps/web and apps/playground-nextjs set incremental, so a warm local tsc reuses tsconfig.tsbuildinfo and is about as fast as bun check, which keeps no cache. CI always starts cold.

A type error still fails the script, including in apps/web:

$ echo 'export const __probe: number = "x"' >> apps/web/next.config.ts
$ bun run --cwd apps/web type-check
Found 1 error in 1 file, checked 280 files [230.96ms]
error: script "type-check" exited with code 1

Merge Danger

Door: two-way

Reverting the commit restores tsc and Bun 1.3.11.

Blast Radius: releases

The publish workflows run bun publish on 1.4.3 from the next canary. ci:publish and ci:publish:canary end each bun publish with || true, so a failed publish would not fail the job. Check that the first canary after this merge reaches npm.

Closes UI-653

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Project	Deployment	Actions	Updated
ui-canary	Ready	Preview	Oct 10, 2026 1:20pm UTC

[linear-code]

UI-653