initHmrBridge registered three Vite HMR listeners (vite:error,
vite:beforeUpdate, vite:beforeFullReload) with no idempotency guard and is
called once per createApp() (dev block in render.ts). createApp() can run
multiple times in one dev process — two apps, an app that unmounts and is
re-created, a tool that restarts the UI, or a test run — and Vite's Node HMR
runtime APPENDS listeners with no dedup, so N calls leaked N copies of every
handler permanently. Every later HMR event then ran each handler N times.
Add a module-level boolean guard so the listeners register at most once for
the module's lifetime, regardless of how many times initHmrBridge is called.
Also parameterize the hot context (defaulting to import.meta.hot) so the body
is reachable under vitest, where import.meta.hot is undefined. HotContext is a
local structural type and import.meta.hot is read via a structural cast so the
module type-checks even when imported directly from runtime-tests, whose
tsconfig doesn't pick up env.d.ts's ambient ImportMeta.hot augmentation.
Out of scope: the setTimeout stale-timer in the vite:beforeUpdate handler is a
separate bug left exactly as-is.
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Yunfei He
8a2efdfeef