deepseek-harness/packages/client/hmr

@deepseek-ai/dsh-client-hmr

Hot reload for fetch-arrival client plugins. A static-arrival entry composed only into --dev graphs (dsh web --dev); production graphs omit the row, so the shell-bundled code stays inert.

The plugin subscribes to the webserver's system SSE channel (GET /plugins/events) and reloads one plugin per rebuilt frame, serialized through a queue (the bundle handoff slot is single). The sequence per frame — prefetch (fetch the new bundle before touching anything), invalidate, registry.delete (before the fiber: a bare fiber dispose trips the vendored Loader's self-dispose branch, which would mark the entry disabled), drain the old fiber, delete entry.fiber, remove owned <style data-plugin> tags, entry.refresh() re-imports and remounts, fiber.await() rethrows startup failures loud. Dependents reload through cordis itself: a fiber's activation epoch strings its service providers' uids, so replacing a provider's fiber cascades every dependent with zero client-side graph analysis. Rebuild detection lives on the webserver: in dev mode it stat-polls each plugin's built lib/client.js (fs.watchFile) and broadcasts the rebuilt frame when the bundle's rev changes, so any tsdown watch process producing the bundle triggers HMR with no builder→host channel.

Model Experience

None, as the reload driver is browser-side machinery; nothing here reaches a model request.

KV Cache effect

None; this package neither assembles nor sends a provider request.

Known Limitations and Deferred Work

• Reload is coarse by design — a fresh fiber and fresh components; React state inside the reloaded plugin is lost while the data layer (connection/runtime fibers, Session objects) is untouched. react-refresh-grade state preservation conflicts with "re-executing the bundle re-runs the factory" and is deliberately out.
• No failure rollback — a reload that fails leaves the entry FAILED and loud in the loader status projection; restoring the previous bundle automatically is deferred until a real need shows.
• Graph rev is not refreshed by rebuilt frames — the stale rev is harmless (the bundle endpoint serves no-cache); rev refresh lands with the reconnect-handshake mechanism.