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bug: using structuredClone with ReadableStream prevents process from exiting #44985
Description
Activity
A workaround is to
teethe cloned stream.Ref: nodejs/undici#1700
It looks like 2 ports aren't unref'd
[ MessagePort [EventTarget] { active: true, refed: true, [Symbol(kEvents)]: SafeMap(4) [Map] { 'newListener' => [Object], 'removeListener' => [Object], 'message' => [Object], 'messageerror' => [Object] }, [Symbol(events.maxEventTargetListeners)]: 10, [Symbol(events.maxEventTargetListenersWarned)]: false, [Symbol(kNewListener)]: [Function (anonymous)], [Symbol(kRemoveListener)]: [Function (anonymous)], [Symbol(nodejs.internal.kCurrentlyReceivingPorts)]: undefined, [Symbol(khandlers)]: SafeMap(2) [Map] { 'message' => [Function], 'messageerror' => [Function] } }, MessagePort [EventTarget] { active: true, refed: true, [Symbol(kEvents)]: SafeMap(4) [Map] { 'newListener' => [Object], 'removeListener' => [Object], 'message' => [Object], 'messageerror' => [Object] }, [Symbol(events.maxEventTargetListeners)]: 10, [Symbol(events.maxEventTargetListenersWarned)]: false, [Symbol(kNewListener)]: [Function (anonymous)], [Symbol(kRemoveListener)]: [Function (anonymous)], [Symbol(nodejs.internal.kCurrentlyReceivingPorts)]: undefined, [Symbol(khandlers)]: SafeMap(2) [Map] { 'message' => [Function], 'messageerror' => [Function] } } ]
which from my best guess are these:
node/lib/internal/webstreams/readablestream.js
Lines 579 to 580 in 2672219
@ronag
I have been able to solve this problem.const { kTransfer } = require("internal/worker/js_transferable"); const { readableStreamPipeTo } = require("internal/webstreams/readablestream"); const { setPromiseHandled, kState } = require("internal/webstreams/util"); const { CrossRealmTransformWritableSink, } = require("internal/webstreams/transfer"); function newCrossRealmWritableSink(readable, port) { const source = new CrossRealmTransformWritableSink(port); const writable = new WritableStream(source); const promise = readableStreamPipeTo(readable, writable, false, false, false); setPromiseHandled(promise); return { writable, source, promise, }; } const registry = new FinalizationRegistry(({ source }) => { source.close(); }); ReadableStream.prototype[kTransfer] = function () { if (this.locked) { this[kState].transfer.port1?.close(); this[kState].transfer.port1 = undefined; this[kState].transfer.port2 = undefined; throw new DOMException( "Cannot transfer a locked ReadableStream", "DataCloneError" ); } const { port1, port2 } = this[kState].transfer; this[kState].transfer.port2 = undefined; const { writable, promise, source } = newCrossRealmWritableSink(this, port1); this[kState].transfer.writable = writable; this[kState].transfer.promise = promise; registry.register(port2, { source }); return { data: { port: port2 }, deserializeInfo: "internal/webstreams/readablestream:TransferredReadableStream", }; }; const stack = [ new Uint8Array([65]), new Uint8Array([65]), new Uint8Array([65]), ]; const rs = new ReadableStream({ pull(controller) { const data = stack.shift(); if (data) { controller.enqueue(data); } else { controller.close(); } }, }); const cloned = structuredClone(rs, { transfer: [rs] });
Reacted by Robert Nagy and Carlos FuentesSorry. Webstreams are beyond my expertise and frankly my interest...
Reacted by tsctx and Carlos FuentesI apologize for the inconvenience that I have caused you.
No worries. No inconvenience at all. 🤗
Reacted by tsctx- added a commit that references this issue
on Dec 24, 2023 - added a commit that references this issue
on Dec 24, 2023 - added a commit that references this issue
on Jan 2, 2024 - added a commit that references this issue
on Mar 18, 2024 - added a commit that references this issue
on Jul 4, 2024
Version
v18.10.0
Platform
Microsoft Windows NT 10.0.19043.0 x64
Subsystem
No response
What steps will reproduce the bug?
After this the process will indefinitely stay open.
How often does it reproduce? Is there a required condition?
always
What is the expected behavior?
the process should exit
What do you see instead?
the process stays open indefinitely
Additional information
Exporting readableStreamTee would also solve my use case.
node/lib/internal/webstreams/readablestream.js
Line 1443 in 214354f