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MessagePort.postMessage with custom iterator as transfer list causes Assertion `(index) < (length())' failed. #49940
Description
Version
v21.0.0-pre (I assume every version w/ structuredClone)
Platform
Linux DESKTOP-L4O1H93 5.10.102.1-microsoft-standard-WSL2 #1 SMP Wed Mar 2 00:30:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Subsystem
No response
What steps will reproduce the bug?
structuredClone({}, {
transfer: {
*[Symbol.iterator]() {}
}
})or
new MessageChannel().port1.postMessage({}, {
transfer: {
*[Symbol.iterator]() {}
}
})How often does it reproduce? Is there a required condition?
No response
What is the expected behavior? Why is that the expected behavior?
this should work and return an empty object
What do you see instead?
./node[4717]: ../../src/util.h:392:T& node::MaybeStackBuffer<T, kStackStorageSize>::operator[](size_t) [with T = v8::Local<v8::Value>; long unsigned int kStackStorageSize = 8; size_t = long unsigned int]: Assertion `(index) < (length())' failed.
1: 0x561c3fcd9e94 node::Abort() [./node]
2: 0x561c3fcd9f28 [./node]
3: 0x561c3fd3310c [./node]
4: 0x561c3fd35a4e node::worker::MessagePort::PostMessage(v8::FunctionCallbackInfo<v8::Value> const&) [./node]
5: 0x561c3ffb4c00 v8::internal::FunctionCallbackArguments::Call(v8::internal::CallHandlerInfo) [./node]
6: 0x561c3ffb54f9 [./node]
7: 0x561c3ffb59e5 v8::internal::Builtin_HandleApiCall(int, unsigned long*, v8::internal::Isolate*) [./node]
8: 0x561c40a14df6 [./node]
Aborted
Additional information
The webidl states that a sequence is basically anything with a Symbol.iterator, not exclusive to arrays. https://webidl.spec.whatwg.org/#es-sequence
Activity
[-]structuredClone with custom iterator as transfer list causes Assertion `(index) < (length())' failed.[/-][+]MessagePort.postMessage with custom iterator as transfer list causes Assertion `(index) < (length())' failed.[/+]targos commentedon Oct 2, 2023
Would it be spec-compliant to just convert the value to an array with
Array.frombefore passing it to the C++ side? It would also take care of potential errors thrown during iteration.KhafraDev commentedon Oct 2, 2023
not entirely, but it's better than nothing. For example, something that isn't null and doesn't have a Symbol.iterator won't throw with Array.from, but spec-wise is expected to (
Array.from(3) // []).KhafraDev commentedon Oct 2, 2023
someone could use
node/lib/internal/crypto/webidl.js
Line 324 in 952cf0d
or maybe using
node/src/node_messaging.cc
Line 947 in 952cf0d