Devtools events lost when using Nitro v3 (worker_threads isolates globalThis)

まず globalThis.TANSTACK_EVENT_TARGET 周辺の EventClient と ServerEventBus を追跡し、次に issue に記載されている nitro() Vite プラグインと Nitro v3 worker_threads セットアップで再現します。worker と Vite のメインスレッドの境界を比較し、サーバー側の Devtools イベントが HTTP workaround なしでパネルに到達することを確認します。

TanStack Devtools version

0.9.13

Framework/Library version

TanStack Start v1.149.3, Nitro v3.0.1-nightly

Describe the bug and the steps to reproduce it

When using TanStack Start with the nitro() Vite plugin (Nitro v3 nightly) rather than nitroV2Plugin, devtools events emitted from server code never reach the devtools panel.

The root cause is that Nitro v3's NodeEnvRunner runs server code in a worker_threads Worker during dev. EventClient dispatches events to globalThis.__TANSTACK_EVENT_TARGET__
inside the worker thread, but ServerEventBus is listening on a different globalThis.__TANSTACK_EVENT_TARGET__ in the Vite main thread. The events are emitted but never received.

This doesn't happen with nitroV2Plugin because that plugin is build-only — in dev, Start uses its own RunnableDevEnvironment which runs in-process and shares the same global scope.

Steps to reproduce:

1. Set up a TanStack Start app using nitro() (Nitro v3) instead of nitroV2Plugin
2. Emit devtools events from server code (e.g. TanStack AI streaming, or any library using @tanstack/devtools-event-client)
3. Open the devtools panel — server-side events are missing

Workaround:
We confirmed the issue by manually bridging events from the Nitro worker to the Vite process over HTTP — intercepting tanstack-dispatch-event on the worker's
globalThis.__TANSTACK_EVENT_TARGET__ and POSTing the payload to a Vite dev server middleware that re-dispatches it on the main thread's event target. This works but is hacky.

Apologies for the double-post — originally mentioned this in Discord, just filing here too since it might be easier to track.

Your Minimal, Reproducible Example - (Sandbox Highly Recommended)

n/a

Screenshots or Videos (Optional)

No response

Do you intend to try to help solve this bug with your own PR?

None

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