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Fix missing CSS when mixing SSR and prerendered routes#15322

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matthewp merged 2 commits intonextfrom
fix-css-env-filtering
Jan 28, 2026
Merged

Fix missing CSS when mixing SSR and prerendered routes#15322
matthewp merged 2 commits intonextfrom
fix-css-env-filtering

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@matthewp
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@matthewp matthewp commented Jan 27, 2026 •
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Summary

  • Fixes missing CSS when a project has both SSR and prerendered routes
  • Instead of returning empty code for duplicate CSS modules (which changed content hashes and broke filename matching), we now filter CSS-to-page assignments by environment type:
    • SSR build: only adds CSS to non-prerendered pages
    • Prerender build: only adds CSS to prerendered pages
    • Client build: adds CSS to all pages (unchanged)

Testing

  • Existing ssr-prerender test suite passes
  • Tested against astro.build which was experiencing missing CSS

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changeset-bot bot commented Jan 27, 2026 •
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🦋 Changeset detected

Latest commit: 14b32c2

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

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@github-actions github-actions bot added feat: markdown Related to Markdown (scope) pkg: svelte Related to Svelte (scope) pkg: vue Related to Vue (scope) pkg: example Related to an example package (scope) 🚨 action Modifies GitHub Actions pkg: react Related to React (scope) pkg: preact Related to Preact (scope) pkg: solid Related to Solid (scope) pkg: integration Related to any renderer integration (scope) pkg: create-astro Related to the `create-astro` package (scope) pkg: astro Related to the core `astro` package (scope) docs pr labels Jan 27, 2026
@matthewp matthewp changed the base branch from main to next January 27, 2026 21:40
@matthewp matthewp added the pr preview Apply this label to a PR to generate a preview release label Jan 27, 2026
@github-actions github-actions bot removed the pr preview Apply this label to a PR to generate a preview release label Jan 27, 2026
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pkg-pr-new bot commented Jan 27, 2026 

npm i https://pkg.pr.new/astro@15322

commit: cd888a2

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alexanderniebuhr commented Jan 28, 2026

@matthewp seems to work astrolicious/dotdev@423376a

ematipico
ematipico approved these changes Jan 28, 2026
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@ematipico ematipico left a comment •
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Awesome. Any is there any chance to add a test? It would be great to avoid possible regressions. Since existing tests were already passing, it probably means that we aren't testing against this particular use case.

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ashhitch commented Jan 28, 2026

@matthewp I have tested the PR on our project. on build, it resolves the styling issues.
However, in dev if a React component does not have a client: directive, then the styles do not render.

@pieh pieh mentioned this pull request Jan 28, 2026
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alexanderniebuhr commented Jan 28, 2026

As for a test for regressions, I think we need two pages one pre-rendered the other on demand which use the same style. Am
I right @matthewp?
Do you have a minimal repro already which we can use as a test?

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matthewp commented Jan 28, 2026

You need more than just having the same styles, you need them to go into separate bundles. I'll see if I can add a test though.

@github-actions github-actions bot removed feat: markdown Related to Markdown (scope) pkg: svelte Related to Svelte (scope) pkg: vue Related to Vue (scope) pkg: example Related to an example package (scope) 🚨 action Modifies GitHub Actions labels Jan 28, 2026
@github-actions github-actions bot removed pkg: react Related to React (scope) pkg: preact Related to Preact (scope) pkg: solid Related to Solid (scope) pkg: integration Related to any renderer integration (scope) pkg: create-astro Related to the `create-astro` package (scope) docs pr labels Jan 28, 2026
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github-actions bot commented Jan 28, 2026

⚠️ Package Trust Level Decreased

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Decreased trust levels may indicate a higher risk of supply chain attacks. Please review these changes carefully.

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@matthewp matthewp merged commit 18e0980 into next Jan 28, 2026
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@matthewp matthewp deleted the fix-css-env-filtering branch January 28, 2026 13:44
@astrobot-houston astrobot-houston mentioned this pull request Jan 28, 2026
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Build fails with ?raw imports when mixing SSR and prerendered routes

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@matthewp @alexanderniebuhr @ashhitch @ematipico