signal with pre aborted

In one of my test, this hangs indefinitely when using a abort signal that have already been canceled togheter with polyfill (this don’t happen when using natives)

  const abortController = new AbortController()
  const signal = abortController.signal
  abortController.abort()
  const promise = rs.pipeTo(ws, { signal })
  err = await promise.catch(e=>e)
  // never gets here

version using 3.0.3 (edit: and 3.0.1 apparently)

[jimmywarting]

That was half Greek/English to me. but Sound like you got it figured out 👍

possible a old duplicate of #56 that i closed and could never figure out what it was

[MattiasBuelens]

Aaaah, I see. The classes from two different versions are seemingly compatible: all public properties and public methods are the same, and even the internal property names like _readableStreamController are unchanged. Except for one small but crucial difference: the private symbols such as [[PullSteps]] and [[ErrorSteps]].

Thus, when version 3.0.0’s ReadableStreamPipeTo() wants to abort a WritableStream from version 3.0.1, it eventually tries to call stream._writableStreamController[ErrorSteps]() in WritableStreamFinishErroring. It will look up the ErrorSteps symbol from version 3.0.0, but that won’t exist on the WritableStream create with version 3.0.1. So this function unexpectedly errors, and the pipe promise never resolves.

I suppose I could improve IsReadableStream to check that stream._readableStreamController is an instance of our own ReadableStreamDefaultController or ReadableByteStreamController, and similarly for IsWritableStream and our own WritableStreamDefaultController. 🤔

Really looking forward to #20 being resolved so i can use that instead. (just patching the missing pieces)

I know, I know. 😛