fix(build): emit before-hydration chunk for client environment by jlukic · Pull Request #15904 · withastro/astro

jlukic · 2026-03-13T15:04:24Z

Overview

Production builds don't emit the before-hydration script chunk to the client output, causing a 404 when islands attempt to load it. This breaks hydration for any integration using injectScript('before-hydration')

Changes

Add ASTRO_VITE_ENVIRONMENT_NAMES.client to the environment guard in buildStart() of vite-plugin-scripts
Add test verifying the before-hydration chunk file exists in the build output

The before-hydration chunk is only emitted for prerender and ssr environments, but not client — which is the environment that produces browser-served JS.

This was introduced in #14306 (Vite Environment API migration), where the original !isSsrBuild condition was changed to ['prerender', 'ssr'].includes(this.environment.name) which mistakenly inverted the original intent.

Testing

Existing tests only assert the attribute is present in HTML, not that the referenced file exists in the client output.

Confirmed all tests pass
Added new test asserting the before-hydration-url resolves in the build output (this test fails without bug fix)

Docs

No docs changes needed — restores existing injectScript('before-hydration', ...) behavior.

changeset-bot · 2026-03-13T15:04:30Z

🦋 Changeset detected

Latest commit: 8eca66b

The changes in this PR will be included in the next version bump.

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Click here if you're a maintainer who wants to add another changeset to this PR

codspeed-hq · 2026-03-13T15:21:01Z

Merging this PR will not alter performance

✅ 18 untouched benchmarks

_{Comparing jlukic:fix/before-hydrate (8eca66b) with main (759f946)}

matthewp

Thanks!

This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [@astrojs/check](https://github.com/withastro/astro/tree/main/packages/language-tools/astro-check) ([source](https://github.com/withastro/astro/tree/HEAD/packages/language-tools/astro-check)) | [`0.9.7` → `0.9.8`](https://renovatebot.com/diffs/npm/@astrojs%2fcheck/0.9.7/0.9.8) | ![age](https://developer.mend.io/api/mc/badges/age/npm/@astrojs%2fcheck/0.9.8?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/@astrojs%2fcheck/0.9.7/0.9.8?slim=true) | | [astro](https://astro.build) ([source](https://github.com/withastro/astro/tree/HEAD/packages/astro)) | [`6.0.4` → `6.0.5`](https://renovatebot.com/diffs/npm/astro/6.0.4/6.0.5) | ![age](https://developer.mend.io/api/mc/badges/age/npm/astro/6.0.5?slim=true) | ![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/astro/6.0.4/6.0.5?slim=true) | --- ### Release Notes <details> <summary>withastro/astro (@astrojs/check)</summary> ### [`v0.9.8`](https://github.com/withastro/astro/blob/HEAD/packages/language-tools/astro-check/CHANGELOG.md#098) [Compare Source](https://github.com/withastro/astro/compare/@astrojs/check@0.9.7...@astrojs/check@0.9.8) ##### Patch Changes - [#15892](withastro/astro#15892) [`a2f597d`](withastro/astro@a2f597d) Thanks [@Princesseuh](https://github.com/Princesseuh)! - Fixes Astro not being able to find astro check sometimes - Updated dependencies \[[`7b4b254`](withastro/astro@7b4b254)]: - [@astrojs/language-server](https://github.com/astrojs/language-server)@2.16.5 </details> <details> <summary>withastro/astro (astro)</summary> ### [`v6.0.5`](https://github.com/withastro/astro/blob/HEAD/packages/astro/CHANGELOG.md#605) [Compare Source](https://github.com/withastro/astro/compare/astro@6.0.4...astro@6.0.5) ##### Patch Changes - [#15891](withastro/astro#15891) [`b889231`](withastro/astro@b889231) Thanks [@matthewp](https://github.com/matthewp)! - Fix dev routing for `server:defer` islands when adapters opt into handling prerendered routes in Astro core. Server island requests are now treated as prerender-handler eligible so prerendered pages using `prerenderEnvironment: 'node'` can load island content without `400` errors. - [#15890](withastro/astro#15890) [`765a887`](withastro/astro@765a887) Thanks [@matthewp](https://github.com/matthewp)! - Fixes `astro:actions` validation to check resolved routes, so projects using default static output with at least one `prerender = false` page or endpoint no longer fail during startup. - [#15884](withastro/astro#15884) [`dcd2c8e`](withastro/astro@dcd2c8e) Thanks [@matthewp](https://github.com/matthewp)! - Avoid a `MaxListenersExceededWarning` during `astro dev` startup by increasing the shared Vite watcher listener limit when attaching content server listeners. - [#15904](withastro/astro#15904) [`23d5244`](withastro/astro@23d5244) Thanks [@jlukic](https://github.com/jlukic)! - Emit the `before-hydration` script chunk for the `client` Vite environment. The chunk was only emitted for `prerender` and `ssr` environments, causing a 404 when browsers tried to load it. This broke hydration for any integration using `injectScript('before-hydration', ...)`, including Lit SSR. - [#15933](withastro/astro#15933) [`325901e`](withastro/astro@325901e) Thanks [@ematipico](https://github.com/ematipico)! - Fixes an issue where `<style>` tags inside SVG components weren't correctly tracked when enabling CSP. - [#15875](withastro/astro#15875) [`c43ef8a`](withastro/astro@c43ef8a) Thanks [@matthewp](https://github.com/matthewp)! - Ensure custom prerenderers are always torn down during build, even when `getStaticPaths()` throws. - [#15887](withastro/astro#15887) [`1861fed`](withastro/astro@1861fed) Thanks [@ematipico](https://github.com/ematipico)! - Fixes an issue where the build incorrectly leaked server entrypoint into the client environment, causing adapters to emit warnings during the build. - [#15888](withastro/astro#15888) [`925252e`](withastro/astro@925252e) Thanks [@matthewp](https://github.com/matthewp)! - Fix a bug where `server:defer` could fail at runtime in prerendered pages for some adapters (including Cloudflare), causing errors like `serverIslandMap?.get is not a function`. - [#15901](withastro/astro#15901) [`07c1002`](withastro/astro@07c1002) Thanks [@delucis](https://github.com/delucis)! - Fixes JSON schema generation for content collection schemas that have differences between their input and output shapes. - [#15882](withastro/astro#15882) [`759f946`](withastro/astro@759f946) Thanks [@matthewp](https://github.com/matthewp)! - Fix `Astro.url.pathname` for the root page when using `build.format: "file"` so it resolves to `/index.html` instead of `/.html` during builds. </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 👻 **Immortal**: This PR will be recreated if closed unmerged. Get [config help](https://github.com/renovatebot/renovate/discussions) if that's undesired. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Co-authored-by: Renovate Bot <renovate@zarantonello.dev> Co-committed-by: Renovate Bot <renovate@zarantonello.dev>

fix(build): emit before-hydration chunk for client environment

13ded0a

github-actions bot added the pkg: astro Related to the core `astro` package (scope) label Mar 13, 2026

Chore: add changeset for hydration fix

9413392

jlukic added a commit to Semantic-Org/Semantic-Next that referenced this pull request Mar 13, 2026

Docs: Add astro patch unless PR merges at withastro/astro#15904

79e7ad4

Merge branch 'main' into fix/before-hydrate

8eca66b

matthewp approved these changes Mar 13, 2026

View reviewed changes

matthewp merged commit 23d5244 into withastro:main Mar 13, 2026
43 of 44 checks passed

This was referenced Mar 13, 2026

[ci] release #15889

Merged

Static build: before-hydration script 404 — chunk not in output #15918

Closed

astrobot-houston mentioned this pull request Mar 22, 2026

Astro 6.0.5+ dev error: context method emitFile() is not supported in serve mode. #16026

Closed

1 task

matthewp mentioned this pull request Mar 24, 2026

Stop emitFile() from running in dev mode in the astro:scripts plugin #16067

Closed

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fix(build): emit before-hydration chunk for client environment#15904

fix(build): emit before-hydration chunk for client environment#15904
matthewp merged 3 commits intowithastro:mainfrom
jlukic:fix/before-hydrate

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jlukic commented Mar 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Overview

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Testing

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Merging this PR will not alter performance

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jlukic commented Mar 13, 2026 •

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