The runtime published its bridge by setting globalThis.newIPN and the
loader read it back immediately after go.run(). That works only because
main() happens to reach the Set call before it blocks, so any package
init that waits on a channel or makes an async JS call would leave the
loader reading a global that is not there yet.
Take the name of a JS callback from go.env instead, and invoke it once
the bridge is built. Readiness is now the call itself, the runtime writes
nothing to the shared global scope, and two runtimes in one realm cannot
collide on a name.
The callback receives a factory that may be used once. shutdown() exits
the whole Go runtime, so a second IPN here would be torn down by the
first one's shutdown; an atomic guard rejects it rather than handing back
an instance that dies unpredictably.
The factory returns a promise, so failures building the engine, netstack,
or LocalBackend reject instead of calling log.Fatal and taking the
runtime down with no explanation for the caller.
Co-Authored-By: claude-opus-5 <noreply@anthropic.com>
codingetandClaude
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