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Fix stale inline CSS in server-rendered HTML during dev#16783

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flue/fix-16780
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Fix stale inline CSS in server-rendered HTML during dev#16783
astrobot-houston wants to merge 1 commit into
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flue/fix-16780

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@astrobot-houston astrobot-houston commented May 19, 2026

Changes

  • Fixes stale inline <style> tags in server-rendered HTML after CSS file edits during dev. CSS changes now properly update both client-side HMR and server-side inline styles, eliminating the flash of old CSS (FOUC) on fresh page loads.
  • Adds invalidation of virtual:astro:dev-css:* modules in both the SSR module graph and module runner evaluation cache when style files change during HMR. This ensures the next SSR render picks up fresh CSS while preserving the performance benefit of skipping full page reloads for CSS-only changes.

Testing

  • Added packages/astro/test/units/dev/hmr-css-invalidation.test.ts with 5 test cases covering CSS/SCSS invalidation, module graph behavior, non-style change passthrough, and edge cases.
  • Tests verify that dev-css virtual modules are properly invalidated when style files change and that non-style changes are unaffected.

Docs

  • No docs update needed, this fixes dev-only behavior to match user expectations.

Closes #16780

@astrobot-houston astrobot-houston added the fix verified Reporter confirmed the triage bot fix works label May 19, 2026
@astrobot-houston astrobot-houston mentioned this pull request May 19, 2026
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changeset-bot Bot commented May 19, 2026

🦋 Changeset detected

Latest commit: 835502c

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

This PR includes changesets to release 417 packages
Name Type
astro Patch
@e2e/astro-linked-lib Patch
@e2e/actions-blog Patch
@e2e/actions-react-19 Patch
@e2e/astro-component Patch
@e2e/astro-envs Patch
@e2e/astro-island-hydration-error Patch
@test/astro-cloudflare-node-prerender-mdx Patch
@test/astro-cloudflare Patch
@e2e/content-collections Patch
@e2e/csp-server-islands Patch
@e2e/css Patch
@test/custom-client-directives Patch
@e2e/dev-toolbar Patch
@e2e/error-cyclic Patch
@e2e/error-sass Patch
@e2e/errors Patch
@e2e/hydration-race Patch
@e2e/i18n Patch
@test/nested-style-bug-e22e Patch
@e2e/preact-compat-component Patch
@e2e/preact-component Patch
@e2e/preact-lazy-component Patch
@e2e/prefetch Patch
@e2e/react-component Patch
@e2e/server-islands-key Patch
@e2e/server-islands Patch
@e2e/solid-circular Patch
@e2e/solid-component Patch
@e2e/solid-recurse Patch
@e2e/svelte-component Patch
@e2e/e2e-tailwindcss Patch
@e2e/ts-resolution Patch
@e2e/view-transitions Patch
@e2e/vite-virtual-modules Patch
@e2e/vue-component Patch
@performance/md Patch
@performance/mdoc Patch
@performance/mdx Patch
@test/0-css Patch
fake-astro-library Patch
@test/actions Patch
@test/alias-path-alias-style Patch
@test/ts-paths-no-baseurl Patch
@test/aliases-tsconfig Patch
@test/aliases Patch
@test/api-routes Patch
@test/asset-query-params-chunks Patch
@test/asset-url-base Patch
@test/astro-pages Patch
@test/astro-assets-prefix Patch
@test/astro-assets Patch
@test/astro-basic Patch
@test/astro-check-errors Patch
@test/astro-check-no-errors Patch
@test/astro-check-watch Patch
@test/astro-children Patch
@test/astro-client-only Patch
@test/astro-component-bundling Patch
@test/astro-component-code Patch
@test/astro-cookies Patch
@test/astro-css-bundling Patch
@test/astro-dev-headers Patch
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@test/astro-env-content-collections Patch
@test/astro-env-required-public Patch
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@test/astro-expr Patch
@test/astro-get-static-paths Patch
@test/astro-head Patch
@test/astro-jsx Patch
@test/astro-manifest-client-script Patch
@test/astro-manifest-invalid Patch
@test/astro-manifest Patch
@test/astro-markdown-frontmatter-injection Patch
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@test/astro-markdown-remarkRehype Patch
@test/astro-markdown-skiki-default-color Patch
@test/astro-markdown-skiki-langs Patch
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@test/astro-markdown-skiki-themes-integrated Patch
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@test/astro-markdown-skiki-wrap-null Patch
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@test/astro-markdown-url Patch
@test/astro-markdown Patch
@test/astro-mode Patch
@test/astro-not-response Patch
@test/astro-page-directory-url Patch
@test/astro-partial-html Patch
@test/astro-preview-allowed-hosts Patch
@test/astro-preview-headers Patch
@test/astro-public Patch
@test/astro-script-template-dedup Patch
@test/astro-scripts Patch
@test/astro-slots-nested Patch
@test/astro-slots Patch
@test/concurrency Patch
@test/build-readonly-file Patch
@test/cache-memory-query-include Patch
@test/cache-memory-query Patch
@test/cache-memory Patch
@test/cache-route Patch
@test/client-address-node Patch
@test/client-address Patch
@test/code-component Patch
@test/component-library Patch
@test/config-vite-css-target Patch
@test/config-vite Patch
@test/react-container Patch
@test/content-with-spaces-in-folder-name Patch
@test/content-collection-picture-render Patch
@example/content-collection-references Patch
@test/content-collection-tla-svg Patch
@test/content-collections-base Patch
@test/content-collections-empty-dir Patch
@test/content-collections-empty-md-file Patch
@test/content-collections-mutation Patch
@test/content-collections-number-id Patch
@test/content-collections-type-inference Patch
@test/content-collections-with-config-mjs Patch
@test/content-collections Patch
@test/content-frontmatter Patch
@test/content-intellisense Patch
@test/content-layer-loader-schema-function Patch
@test/content-layer-remark-plugins Patch
@test/content-layer Patch
@test/content-ssr-integration Patch
@test/content-static-paths-integration Patch
@test/content Patch
@test/core-image-data-url Patch
@test/core-image-deletion-ssr Patch
@test/core-image-deletion Patch
@test/core-image-errors Patch
@test/core-image-fs-config Patch
@test/core-image-remark-infersize Patch
@test/core-image-layout Patch
@test/core-image-picture-emit-file Patch
@test/core-image-remark-imgattr Patch
@test/core-image-ssg Patch
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@test/core-image-svg-in-client Patch
@test/core-image-svg Patch
@test/core-image-unconventional-settings Patch
@test/core-image Patch
@test/csp-adapter Patch
@test/csp-fonts Patch
@test/csp Patch
@test/css-assets Patch
@test/css-dangling-references Patch
@test/css-deduplication Patch
@test/css-double-bundle Patch
@test/css-dynamic-import-dev Patch
@test/css-import-as-inline Patch
@test/css-inline-stylesheets Patch
@test/css-no-code-split Patch
@test/custom-404-injected-from-dep Patch
@test/custom-404-pkg Patch
@test/custom-500-failing Patch
@test/custom-500 Patch
custom-fetch-error-pages Patch
@test/custom-renderer Patch
@test/data-collections-schema Patch
@test/data-collections Patch
@test/debug-component Patch
@test/dev-container Patch
@test/dev-render Patch
@test/dev-request-url Patch
@test/dynamic-endpoint-collision Patch
@test/dynamic-route-build-file Patch
@test/endpoint-routing Patch
@test/error-bad-js Patch
@test/error-build-location Patch
@test/error-non-error Patch
@test/extension-matching Patch
@test/fetch Patch
@test/fonts Patch
@test/astro-fontsource-package Patch
@test/get-static-paths-pages Patch
@test/glob-pages-css Patch
@test/head-propagation-prerender-env Patch
@test/hmr-markdown Patch
@test/hmr-new-page Patch
@test/hmr-slots-render Patch
@test/hoisted-imports Patch
@test/html-component Patch
@test/html-escape Patch
@test/html-page Patch
@test/html-slots Patch
@test/hydration-race Patch
@test/i18n-css-leak-basic Patch
@test/import-ts-with-js Patch
@test/impostor-md-file Patch
@test/integration-add-page-extension Patch
@test/integration-server-setup Patch
@test/jsx-queue-rendering Patch
@test/large-array-solid Patch
@test/legacy-collections-backwards-compat Patch
@test/lightningcss-scoped-nesting Patch
@test/live-loaders Patch
@test/markdown Patch
@test/middleware-dev Patch
@test/middleware-full-ssr Patch
@test/middleware-no-user-middlewaqre Patch
@test/middleware-sequence-rewrite Patch
@test/middleware-tailwind Patch
@test/minification-html-jsx Patch
@test/minification-html Patch
@test/non-ascii-path Patch
@test/non-html-pages Patch
@test/page-format Patch
@test/page-level-styles Patch
@test/parallel-components Patch
@test/partials-css-boundary Patch
@test/partials Patch
@test/passthrough-image-service Patch
@test/postcss Patch
@test/preact-compat-component Patch
@test/preact-component Patch
@test/queue-rendering Patch
@test/remote-css Patch
@test/request-signal Patch
@test/reuse-injected-entrypoint Patch
@test/rewrite-runtime-error-custom500 Patch
@test/rewrite-runtime-error Patch
@test/reroute-server Patch
@test/rewrite-trailing-slash-never Patch
@test/rewrite-with-base Patch
@test/root-srcdir-css Patch
@test/scoped-style-strategy Patch
@test/server-entry-fake-adapter Patch
@test/server-entry Patch
@test/server-islands-hybrid Patch
@test/server-islands-ssr Patch
@test/sessions Patch
@test/slots-preact Patch
@test/slots-react Patch
@test/slots-solid Patch
@test/slots-svelte Patch
@test/slots-vue Patch
@test/solid-component Patch
@test/sourcemap Patch
@test/space-in-folder-name Patch
@test/special-chars-in-component-imports Patch
@test/ssr-api-route Patch
@test/ssr-assets Patch
@test/ssr-dynamic Patch
@test/ssr-partytown Patch
@test/ssr-prerender-get-static-paths Patch
@test/ssr-prerender Patch
@test/ssr-preview Patch
@test/ssr-renderers-static-vue Patch
@test/ssr-request Patch
@test/ssr-hoisted-script Patch
@test/ssr-scripts Patch
@test/static-build-code-component Patch
@test/static-build-dir Patch
@test/static-build-frameworks Patch
@test/static-build-page-url-format Patch
@test/static-build-ssr Patch
@test/static-build Patch
@test/static-redirect Patch
@test/streaming Patch
@test/svelte-component Patch
@test/svg-deduplication Patch
@test/tailwindcss Patch
@e2e/third-party-astro Patch
@test/url-import-suffix Patch
@test/view-transitions Patch
@test/virtual-astro-file Patch
@test/vitest Patch
@test/vue-component Patch
@test/vue-with-multi-renderer Patch
@test/db-aliases Patch
@test/db-db-in-src Patch
@test/error-handling Patch
@test/db-integration-only Patch
@test/db-integration Patch
@test/db-libsql-remote Patch
@test/db-local-prod Patch
@test/db-no-apptoken Patch
@test/db-no-seed Patch
@test/recipes Patch
@test/db-static-remote Patch
@test/alpinejs-basics Patch
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@test/alpinejs-plugin-script-import Patch
@test/astro-cloudflare-allowed-hosts Patch
@test/astro-cloudflare-astro-dev-platform Patch
@test/astro-cloudflare-astro-env Patch
@test/astro-cloudflare-binding-image-service Patch
@test/astro-cloudflare-cache-provider-wait-until Patch
@test/astro-cloudflare-client-address Patch
@test/astro-cloudflare-compile-image-service Patch
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@test/astro-cloudflare-dev-image-endpoint Patch
@test/cloudflare-dev-ssr-optimization Patch
@test/astro-cloudflare-external-image-service Patch
@test/astro-cloudflare-external-redirects Patch
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@test/astro-cloudflare-no-output Patch
@test/astro-cloudflare-prerender-node-env Patch
@test/astro-cloudflare-prerender-queue-consumers Patch
@test/astro-cloudflare-prerender-styles Patch
@test/astro-cloudflare-prerenderer-errors Patch
@test/routing-priority-cloudflare Patch
@test/cf-server-entry Patch
@test/astro-cloudflare-server-island-prerender-framework Patch
@test/astro-cloudflare-sql-import Patch
@test/cf-ssr-deps Patch
@test/astro-cloudflare-static Patch
@test/astro-cloudflare-svelte-rune-deps Patch
@test/astro-cloudflare-top-level-return Patch
@test/astro-cloudflare-vite-plugin Patch
@test/astro-cloudflare-with-base Patch
@test/astro-cloudflare-with-react Patch
@test/astro-cloudflare-with-solid-js Patch
@test/astro-cloudflare-with-svelte Patch
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@test/astro-cloudflare-wrangler-preview-platform Patch
@test/markdoc-content-collections Patch
@test/content-layer-markdoc Patch
@test/headings-custom Patch
@test/headings Patch
@test/image-assets-custom Patch
@test/image-assets Patch
@test/markdoc-propagated-assets Patch
@test/markdoc-render-with-space Patch
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@test/markdoc-render-null Patch
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@test/markdoc-render-simple Patch
@test/markdoc-render-table-attrs Patch
@test/markdoc-render-typographer Patch
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@test/markdoc-render-with-config Patch
@test/markdoc-render-with-extends-components Patch
@test/markdoc-render-with-indented-components Patch
@test/markdoc-render-with-transform Patch
@test/markdoc-variables Patch
@test/content-layer-rendering Patch
@test/mdx-css-head-mdx Patch
@test/image-remark-imgattr Patch
@test/mdx-astro-container-escape Patch
@test/mdx-frontmatter-injection Patch
@test/netlify-skew-protection Patch
@test/netlify-hosted-astro-project Patch
@test/nodejs-api-route Patch
@test/nodejs-badurls Patch
@test/nodejs-encoded Patch
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@test/nodejs-image Patch
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@test/nodejs-prerender-404-500 Patch
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@test/nodejs-prerendered-error-page-fetch Patch
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@test/redirects Patch
@test/node-sessions Patch
@test/ssr-assets-middleware Patch
@test/node-static-headers Patch
@test/node-trailingslash Patch
@test/url Patch
@test/well-known-locations Patch
@test/react-component Patch
@test/sitemap-chunks Patch
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@test/sitemap-i18n-fallback Patch
@test/sitemap-ssr Patch
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@test/sitemap-trailing-slash Patch
async-rendering Patch
conditional-rendering Patch
@test/empty-class Patch
svelte-prop-types Patch
@test/astro-vercel-basic Patch
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@test/astro-vercel-integration-assets Patch
@test/vercel-isr Patch
@test/vercel-max-duration Patch
@test/vercel-edge-middleware-with-edge-file Patch
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@test/astro-vercel-prerendered-error-pages Patch
@test/astro-vercel-redirects-serverless Patch
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vercel-hosted-astro-project Patch
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vue-prop-types Patch
astro-benchmark Patch
@benchmark/adapter Patch
@benchmark/timer Patch
benchmark-build-hybrid Patch
benchmark-build-server Patch
benchmark-build-static Patch

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@github-actions github-actions Bot added the pkg: astro Related to the core `astro` package (scope) label May 19, 2026
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codspeed-hq Bot commented May 19, 2026

Merging this PR will not alter performance

✅ 18 untouched benchmarks

Comparing flue/fix-16780 (835502c) with main (068d924)

Open in CodSpeed

@thelazylamaGit thelazylamaGit mentioned this pull request May 21, 2026
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Bug: Global CSS HMR stale on getStaticPaths() routes in Astro 6

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