refactor(astro): replace tsconfck with get-tsconfig by ocavue · Pull Request #16433 · withastro/astro

ocavue · 2026-04-21T06:21:18Z

Summary

Replaces the discontinued tsconfck dependency with get-tsconfig@5.0.0-beta.4 and jsonc-parser. This is a step forward to support TS 6.0 as tsconfck doesn't support TS 6 in its peerDep.

Closes #16385

Why beta

I need to use get-tsconfig v5 beta instead of the v4 stable because get-tsconfig v4 leaks a feature that resolves all extended file paths for the purpose of dev server watch files (see privatenumber/get-tsconfig#119).

If astro team doesn't want to ship a beta dependency, we can wait for the get-tsconfig v5 stable.

What's changed

Use jsonc-parser to parse the raw tsconfig file
Use get-tsconfig to resolve the tsconfig (i.e., merge extends) and get a list of all files from extends.
Remove 'unknown-error' error type
Print the error message via logger if failed to parse the tsconfig file.

Notes for maintainers

get-tsconfig is pinned to exactly 5.0.0-beta.4 (no caret).
jsonc-parser is added as a direct dep. It was already transitively present via Vite, so no new bytes on disk.

Test

Existing tests should pass
Added two tests

Docs

~~Changeset added.~~

changeset-bot · 2026-04-21T06:21:24Z

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Latest commit: d15b124

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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github-actions

This PR is blocked because it contains a minor changeset. A reviewer will merge this at the next release if approved.

codspeed-hq · 2026-04-21T06:41:40Z

Merging this PR will not alter performance

✅ 18 untouched benchmarks

_{Comparing ocavue-forks:ocavue/get-tsconfig-4 (d15b124) with main (1058428)}

ocavue · 2026-04-21T08:00:20Z

 	compilerOptions?: StripEnums<CompilerOptions>;
 	compileOnSave?: boolean;
-	extends?: string;
+	extends?: string | string[];


Note for reviewers:

extends can be an array since TS 5.0

ocavue · 2026-04-21T08:15:27Z

 */
-export async function loadTSConfig(
-	root: string | undefined,
-	findUp = false,


Note for reviewers:

findUp is never passed; it was always false. I removed findUp in this PR.

ocavue · 2026-04-21T08:49:02Z

+		tsconfigFile: normalize(resolved.path),
+		tsconfig: resolved.config satisfies TSConfig,
+		rawConfig,
+		sources: (resolved.sources || [resolved.path]).map(normalize),


Note for reviewers:

Here I use normalize to return the backward slash \ on Windows. This aligns with the previous behavior. I don't see any issue with returning / on Windows, but it's good to be cautious just in case.

ematipico · 2026-04-22T16:35:15Z

If there's no user facing change, we can skip the changeset

deleted the changeset file

…onfig-4

delucis

@ocavue Did you investigate the option of using the rolldown utilities as suggested in the tsconfck issue: dominikg/tsconfck#240? The issue links Vite’s PR where they did this: vitejs/vite#21577.

That would have to be against next where we have Vite 8 + Rolldown available but could be worth doing to avoid the extra dep. (If it covers everything we need — I haven’t looked yet, but I had it on my todo list.)

ocavue · 2026-04-24T15:13:56Z

That's also on my todo list. I will check it out.

ocavue · 2026-04-24T17:43:58Z

vite uses resolveTsconfig from rolldown/experimental to replace tsconfck.

I have two concerns about reusing this API in Astro:

resolveTsconfig is marked as @hidden and noted as "only expected to be used by Vite". This suggests the Vite/Rolldown team may introduce breaking changes to this API even in a patch release.
vite does not re-export resolveTsconfig. To use it, we would need to add rolldown as a direct dependency of astro. This could result in 2 different versions of rolldown in users'node_modules (e.g., astro -> rolldown and astro -> vite -> rolldown).

Eveeifyeve

IA with #16433 (comment) I feel IMHO this change should be blocked until there is a clear more direction from the vite team.

## Summary - resolves TypeScript from 5.9.2 to 5.9.3 in `pnpm-lock.yaml` - keeps the existing `package.json` range on TypeScript 5 so Astro tooling remains inside its declared peer dependency support ## Why not TypeScript 6 yet? TypeScript 6 is the npm latest, but it is a real migration release rather than a routine patch update. The TypeScript 6 notes call out changed compiler defaults, root directory behavior, stricter side-effect import handling, deprecated options, and other migration concerns. Astro support is also still catching up: - withastro/astro#16112 tracks `@astrojs/check@0.9.8` still requiring `typescript@^5.0.0`. - withastro/astro#16385 tracks Astro still depending on `tsconfck`, which also declares `typescript@^5.0.0` and is being discontinued. - withastro/astro#16433 is the open upstream PR to replace `tsconfck` with `get-tsconfig`; it is not merged yet. Keeping this PR to TypeScript 5.9.3 gets the latest supported 5.x patch without opting into peer dependency overrides or upstream compatibility assumptions. ## Validation - `mise exec -- corepack pnpm install --frozen-lockfile` - `mise exec -- corepack pnpm test -- --run` - `mise exec -- corepack pnpm format:check` - `mise run build`

dominikg · 2026-04-27T12:10:24Z

i think it makes sense for vite to expose it and started a feature request here
vitejs/vite#22336 please add any relevant information of apis you want/need, things like shared caching or change detection come to my mind but not intimately familiar with astro or its needs

github-actions Bot added pkg: astro Related to the core `astro` package (scope) semver: minor Change triggers a `minor` release labels Apr 21, 2026

github-actions Bot requested changes Apr 21, 2026

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ocavue marked this pull request as ready for review April 21, 2026 06:38

ocavue marked this pull request as draft April 21, 2026 06:40

ocavue force-pushed the ocavue/get-tsconfig-4 branch from 485c17f to 87dd769 Compare April 21, 2026 07:12

github-actions Bot added pkg: integration Related to any renderer integration (scope) and removed pkg: integration Related to any renderer integration (scope) labels Apr 21, 2026

ocavue force-pushed the ocavue/get-tsconfig-4 branch from d9ddf6f to a2c55af Compare April 21, 2026 07:55

ocavue commented Apr 21, 2026

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ocavue force-pushed the ocavue/get-tsconfig-4 branch from 75707a9 to ceb6749 Compare April 21, 2026 09:03

refactor(astro): replace tsconfck with get-tsconfig

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ocavue force-pushed the ocavue/get-tsconfig-4 branch from ceb6749 to 330a927 Compare April 21, 2026 10:17

chore: trigger ci

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ocavue marked this pull request as ready for review April 21, 2026 11:42

ematipico reviewed Apr 22, 2026

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ocavue and others added 2 commits April 23, 2026 09:06

Delete replace-tsconfck-with-get-tsconfig.md

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Merge branch 'main' of github.com:withastro/astro into ocavue/get-tsc…

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…onfig-4

ematipico approved these changes Apr 23, 2026

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ocavue added 4 commits April 24, 2026 02:21

Merge branch 'main' into ocavue/get-tsconfig-4

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Merge branch 'main' into ocavue/get-tsconfig-4

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Merge branch 'main' into ocavue/get-tsconfig-4

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Merge branch 'main' into ocavue/get-tsconfig-4

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delucis reviewed Apr 24, 2026

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Merge branch 'main' into ocavue/get-tsconfig-4

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Eveeifyeve reviewed Apr 25, 2026

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joshka mentioned this pull request Apr 26, 2026

Refresh TypeScript lockfile ratatui/ratatui-website#1132

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dominikg mentioned this pull request Apr 27, 2026

expose resolveTsconfig util for reuse by plugins/frameworks vitejs/vite#22336

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Summary

Why beta

What's changed

Notes for maintainers

Test

Docs

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dominikg commented Apr 27, 2026

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