HMR not working properly with named exports referencing variable declaration where the export comes first

[c5n8]

Related plugins

• plugin-vue

• plugin-vue-jsx

Describe the bug

// Foo.tsx
export { Foo }

const Foo = defineComponent(/* ... */)

This will also reload parent module, and can bubble up to page reload.

Reproduction

https://stackblitz.com/edit/vitejs-vite-hwbp51q3?file=src%2Fcomponents%2Ffoo.tsx

Steps to reproduce

No response

System Info

System:
  OS: Linux 5.0 undefined
  CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
  Memory: 0 Bytes / 0 Bytes
  Shell: 1.0 - /bin/jsh
Binaries:
  Node: 20.19.1 - /usr/local/bin/node
  Yarn: 1.22.19 - /usr/local/bin/yarn
  npm: 10.8.2 - /usr/local/bin/npm
  pnpm: 8.15.6 - /usr/local/bin/pnpm

Used Package Manager

npm

Logs

No response

Validations

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• The provided reproduction is a minimal reproducible example of the bug.

[wgrea]

This looks like a subtle HMR edge case tied to export timing. I flipped the declaration order:

const Foo = defineComponent(/* ... */)
export { Foo }

With this structure, HMR behaves as expected—no parent reload. That suggests Vite’s graph may treat early exports as unresolved, triggering a reload cascade.

Hypothesis: When export { Foo } comes before const Foo = ..., Vite’s HMR boundary detection might encounter a temporal dead zone—especially with JSX transforms in play. Could be worth inspecting how plugin-vue-jsx handles named exports during transform.

Also curious if switching to export const Foo = ... or using default exports changes the behavior. Let me know if you'd like help isolating the transform step or mapping the reload cascade—happy to dig deeper.