fix(runtime): warn on unsupported web Worker options and fix recv panic#33310
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Emit a console warning when node-specific options like `env` or `workerData` are passed to the web `Worker()` constructor, directing users to `node:worker_threads` instead. These options are silently ignored by web Workers, which can lead to subtle bugs like infinite worker recursion (fixes #31058). Also replace `handle_receiver.recv().unwrap()` in `op_create_worker` with a proper error return, so a worker thread dying before initialization produces a JS error instead of a process panic. Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
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Summary
env,workerData) are passed to the webWorker()constructor, directing users tonode:worker_threadsinstead. These options are silently ignored by web Workers, which can lead to subtle bugs like infinite worker recursion.handle_receiver.recv().unwrap()inop_create_workerwith a proper error return, so a worker thread dying before initialization produces a JS error instead of a process panic.Fixes #31058
Root cause
The issue reporter passed
{ env: { IS_WORKER: "true" } }tonew Worker()(web worker). The web Worker constructor silently ignoresenv(it's a node:worker_threads option). The spawned worker couldn't detect it was a worker (process.env.IS_WORKERwas never set), so it entered the main code path and recursively spawned more workers exponentially. This exhausted OS resources until Rust's thread initialization panicked trying to allocate a signal stack.Test plan
tests/specs/worker/worker_unsupported_options/— verifies warning for bothenvandworkerDatanode:worker_threadsspec tests passcargo check -p deno_runtimeclean🤖 Generated with Claude Code