`Failed to read data from the ReadableStream: “TypeError: attempting to access detached ArrayBuffer”.` when fetch() are called simultaneously on Firefox

[Utaea]

useEffect(() => {
    fetch(`http://localhost:5173/1.db.xz`)
      .then(compressedResponse => {
        const decompressedResponse = new Response(
          new XzReadableStream(compressedResponse.body!)
        );
        return decompressedResponse.arrayBuffer();
      })
      .catch(error => {
        console.error('Error:', error);
      });
    
    fetch(`http://localhost:5173/2.db.xz`)
      .then(compressedResponse => {
        const decompressedResponse = new Response(
          new XzReadableStream(compressedResponse.body!)
        );
        return decompressedResponse.arrayBuffer();
      })
      .catch(error => {
        console.error('Error:', error);
      });
}, []);

Code above works fine on Chrome, but on Firefox this will lead to Failed to read data from the ReadableStream: “TypeError: attempting to access detached ArrayBuffer”., and this error will occur only when multiple fetch() (or multiple decompression thread?) are running simultaneously

[pimterry]

@Utaea, what happens if you add a this._refresh() call at the start of supplyInput as suggested here? Given that that only affected one person using Deno I had assumed this was a niche issue, but if it's reproducible in browsers that's more convincing.

emscripten-core/emscripten#6747 has some clues about things that can cause this - e.g. WASM memory growth when some memory is currently in use. If that works for you, PRs to fix this are welcome.

[Utaea]

I tried the solution suggested by #1 and this time the error message changed to Failed to read data from the ReadableStream: “Error: get_next_output failed with error code 8”. According to xz.h , this indicates XZ_BUF_ERROR, and

under multi-call mode, XZ_BUF_ERROR is returned when two consecutive calls to XZ code cannot consume any input and cannot produce any new output. This happens when there is no new input available, or the output bufferis full while at least one output byte is still pending. Assuming your code is not buggy, you can get this error only when decoding a compressed stream that is truncated or otherwise corrupt.

I'm sure the compressed stream is not corrupted since there's no error when only one fetch() is running. I also checked emscripten-core/emscripten#6747 but I think it not related to our issue or maybe I'm wrong. Currently I have no more clues on this issue.

[pimterry]

In the end I have set up a proper reproducible test for this with Node, and I've managed to confirm the issue there in automated tests, and resolve it with the this._refresh() fix suggested.

For now I've released that as v0.2.2, since it definitely solves some issues (it fixes that test, that now otherwise failed reliably every time). If you can still reproduce this issue, can you test that new release, just to confirm it still doesn't work in this case? I'm not sure why Firefox would be different, but if we can confirm that's still a broken case for you then we can investigate further from there.