fix: buffer rsc:update payloads arriving before dev client mounts#161
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In devMain, the rsc:update HMR listener was registered before the component's mount effect assigned setPayload, so an update event racing the initial render called undefined and threw, dropping the update. Keep the fetched payload in a pending variable when the setter is not ready yet and apply it from the mount effect. Fixes #145 Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01CAcPFym3wyHJQyMb2FdgqT
uhyo
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Jul 21, 2026
| )}`; | ||
| const payload = await createFromFetch<RscPayload>(fetch(rscUrl)); | ||
| setPayload(payload); | ||
| if (setPayload) { |
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How about moving the pre-effect logic into the initial value of setPayload instead of branching here?
Per review, replace the undefined check in fetchRscPayload with an initial setPayload implementation that stashes the payload until the mount effect swaps in the real setter. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01CAcPFym3wyHJQyMb2FdgqT
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Summary
Fixes #145.
In
devMain(packages/static/src/client/entry.tsx), thersc:updateHMR listener is registered immediately, butsetPayloadwas only assigned inside the component's mount effect. An update event arriving before the first effect ran (e.g. a server-code edit racing initial render, or a slow mount on the SSR failure path) calledsetPayloadwhile it was stillundefined, throwing aTypeErrorand dropping the update.Changes
fetchRscPayloadnow checks whethersetPayloadis assigned; if not, the fetched payload is stored in apendingPayloadvariable instead of crashing.setPayload, so early updates are rendered rather than dropped.Testing
pnpm typecheckpnpm lintpnpm test:run(102 tests passed)🤖 Generated with Claude Code
https://claude.ai/code/session_01CAcPFym3wyHJQyMb2FdgqT
Generated by Claude Code