[turbopack] Fix CSS HMR on Safari#92123
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lukesandberg merged 1 commit intocanaryfrom Mar 31, 2026
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Looks good, can we add a test to catch this? |
Merging this PR will degrade performance by 4.26%
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not easily. afaict we don't have any hmr tests for safari or firefox in CI |
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i did manually test this with firefox and safari (and chrome) so css loading is working, but yeah it is a risk |
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ok, this is easy we actualyl already have css hmr tests, just not for firefox and safari |
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mmastrac
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Fixes #91818 **Regression source:** Commit `b7e4c6a011` ("Turbopack: transpile CHUNK_SUFFIX") introduced `getChunkSuffixFromScriptSrc()` which reads query strings from `<script>` tags. On Safari, this picks up the `?ts=` param injected by the server-side cache-busting workaround in `render.tsx` (for [WebKit into `ASSET_SUFFIX`. This causes HMR CSS URLs to match the preloaded URL exactly, re-triggering the Safari preload cache bug and preventing style updates. **Changes:** - **`dev-backend-dom.ts`**: Match existing `<link>` elements by base path (strip query string) so selectors work across HMR updates with different `?ts=` values. Add Safari to the Firefox cache-busting branch so new stylesheet links always get a fresh `?ts=`. - **`hmr-client.ts`**: Fix `mergeChunkUpdates` so a `total` update always supersedes any prior update type. (cherry picked from commit 8be5a3c)
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## Summary - Backport of #92123 to `next-16-2` release branch - Cherry-picked the CSS HMR Safari fix and regenerated turbopack-tests snapshot goldens for the release branch ## Test plan - [x] `UPDATE=1 cargo nextest r -p turbopack-tests` — all 297 tests pass - [x] `pnpm build-all` — clean build, no issues with `generated-native.d.ts`
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Fixes #91818
Regression source: Commit
b7e4c6a011("Turbopack: transpile CHUNK_SUFFIX") introducedgetChunkSuffixFromScriptSrc()which reads query strings from<script>tags. On Safari, this picks up the?ts=param injected by the server-side cache-busting workaround inrender.tsx(for WebKit #187726), baking it intoASSET_SUFFIX. This causes HMR CSS URLs to match the preloaded URL exactly, re-triggering the Safari preload cache bug and preventing style updates.Changes:
dev-backend-dom.ts: Match existing<link>elements by base path (strip query string) so selectors work across HMR updates with different?ts=values. Add Safari to the Firefox cache-busting branch so new stylesheet links always get a fresh?ts=.hmr-client.ts: FixmergeChunkUpdatesso atotalupdate always supersedes any prior update type.