_a.cancel is not a function in v2.0.2

[joachimvh]

In https://github.com/solid/community-server/pull/791 I had to roll fetch-sparql-endpoint back to 2.0.1 because the sparql integration test failed with the following error:

FAIL test/integration/SparqlStorage.test.ts (5.307 s)
  ● A server with a SPARQL endpoint as storage › can add a Turtle file to the store.

    TypeError: _a.cancel is not a function

      314 |     this.logger.info(`Sending SPARQL UPDATE query to ${this.endpoint}: ${query}`);
      315 |     try {
    > 316 |       return await this.fetcher.fetchUpdate(this.endpoint, query);
          |              ^
      317 |     } catch (error: unknown) {
      318 |       this.logger.error(`SPARQL endpoint ${this.endpoint} error: ${createErrorMessage(error)}`);
      319 |       throw error;

      at SparqlEndpointFetcher.handleFetchCall (node_modules/fetch-sparql-endpoint/lib/SparqlEndpointFetcher.js:169:85)
          at runMicrotasks (<anonymous>)
      at SparqlEndpointFetcher.fetchUpdate (node_modules/fetch-sparql-endpoint/lib/SparqlEndpointFetcher.js:130:9)
      at SparqlDataAccessor.sendSparqlUpdate (src/storage/accessors/SparqlDataAccessor.ts:316:14)
      at DataAccessorBasedStore.writeData (src/storage/DataAccessorBasedStore.ts:320:5)
      at runWithTimeout (src/util/locking/WrappedExpiringReadWriteLocker.ts:67:16)
      at GreedyReadWriteLocker.withWriteLock (src/util/locking/GreedyReadWriteLocker.ts:62:14)
      at MonitoringStore.setRepresentation (src/storage/MonitoringStore.ts:45:29)
      at RootContainerInitializer.createRootContainer (src/init/RootContainerInitializer.ts:54:5)
      at RootContainerInitializer.handle (src/init/RootContainerInitializer.ts:33:7)
          at async Promise.all (index 0)
      at SequenceHandler.handle (src/util/handlers/SequenceHandler.ts:27:18)
      at App.start (src/init/App.ts:20:5)
      at test/integration/SparqlStorage.test.ts:31:5

This was the integration test on Node 16.0. The other ones didn't finish because of this so it could also be that this is because of a bug in 16.0, I did not test this in-depth yet.

[rubensworks]

That's interesting. Can you check manually if it also throws for Node 16? Because I'm running this without issues in Comunica.

In any case, it's part of the standard Fetch API: https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream/cancel

Could it be perhaps an issue with your test mocks?

[joachimvh]

Could it be perhaps an issue with your test mocks?

This is an integration test so it should be completely without mocks.

Note that this would not be the first time there's something wrong with a .0 Node version so it could also be that, can have a look later.

[joachimvh]

Did some small tests already. Using Node 14.15.1 doing a PUT request to a store with a sparql backend (same docker container as the CI tests). I get the same error on Ubuntu but on Windows it works. So that is going to make it interesting to find out what exactly the issue is.

[rubensworks]

Any way you could inspect the raw response body, to see what kind of object it is, and if cancel really does not exist?

[joachimvh]

I forgot to update the Windows setup to version 2.0.2 of course, explaining the discrepancy 🙄 . Fails on both now. Here's the full response object, no cancel function found.

<ref *1> Gunzip {
  _writeState: Uint32Array(2) [ 0, 0 ],
  _readableState: ReadableState {
    objectMode: false,
    highWaterMark: 16384,
    buffer: BufferList { head: null, tail: null, length: 0 },
    length: 0,
    pipes: [],
    flowing: null,
    ended: false,
    endEmitted: false,
    reading: false,
    sync: false,
    needReadable: false,
    emittedReadable: false,
    readableListening: false,
    resumeScheduled: false,
    errorEmitted: false,
    emitClose: true,
    autoDestroy: true,
    destroyed: false,
    errored: null,
    closed: false,
    closeEmitted: false,
    defaultEncoding: 'utf8',
    awaitDrainWriters: null,
    multiAwaitDrain: false,
    readingMore: false,
    decoder: null,
    encoding: null,
    [Symbol(kPaused)]: null
  },
  _events: [Object: null prototype] {
    prefinish: [Function: prefinish],
    unpipe: [Function: onunpipe],
    error: [ [Function: onerror], [Function (anonymous)] ],
    close: [Function: bound onceWrapper] { listener: [Function: onclose] },
    finish: [Function: bound onceWrapper] { listener: [Function: onfinish] }
  },
  _eventsCount: 5,
  _maxListeners: undefined,
  _writableState: WritableState {
    objectMode: false,
    highWaterMark: 16384,
    finalCalled: false,
    needDrain: false,
    ending: false,
    ended: false,
    finished: false,
    destroyed: false,
    decodeStrings: true,
    defaultEncoding: 'utf8',
    length: 0,
    writing: false,
    corked: 0,
    sync: true,
    bufferProcessing: false,
    onwrite: [Function: bound onwrite],
    writecb: null,
    writelen: 0,
    afterWriteTickInfo: null,
    buffered: [],
    bufferedIndex: 0,
    allBuffers: true,
    allNoop: true,
    pendingcb: 0,
    prefinished: false,
    errorEmitted: false,
    emitClose: true,
    autoDestroy: true,
    errored: null,
    closed: false
  },
  allowHalfOpen: true,
  bytesWritten: 0,
  _handle: Zlib {
    onerror: [Function: zlibOnError],
    [Symbol(owner_symbol)]: [Circular *1]
  },
  _outBuffer: <Buffer 00 27 db ff 49 ff 00 27 92 77 e8 42 00 02 00 80 a0 80 fd f3 24 02 00 00 00 00 00 00 00 00 00 00 00 20 00 00 00 00 00 00 a0 80 fd f3 24 02 00 00 28 42 ... 16334 more bytes>,
  _outOffset: 0,
  _chunkSize: 16384,
  _defaultFlushFlag: 2,
  _finishFlushFlag: 2,
  _defaultFullFlushFlag: 3,
  _info: undefined,
  _maxOutputLength: 4294967295,
  _level: -1,
  _strategy: 0,
  [Symbol(kCapture)]: false,
  [Symbol(kTransformState)]: {
    afterTransform: [Function: bound afterTransform],
    needTransform: false,
    transforming: false,
    writecb: null,
    writechunk: null,
    writeencoding: null
  },
  [Symbol(kError)]: null
}

I also tried passing our fetch function to the constructor since it's a later version of cross-fetch but it still has the same issue.

[rubensworks]

So it looks like cancel is indeed not supported by node-fetch, since it's apparently not strictly part of the fetch API (which indicates that there are problems with the TS typings).

One possible workaround would be to use the new abort controllers: https://github.com/node-fetch/node-fetch#request-cancellation-with-abortsignal

[rubensworks]

Fixed in 2.1.0. (also added some small integration tests to confirm this behaviour and avoid regressions)

[rubensworks]

For future reference, it looks like body (which is a ReadableStream) should in fact expose a .cancel() method according to the spec:

• https://fetch.spec.whatwg.org/#body
• https://streams.spec.whatwg.org/#readablestream It's just node-fetch that doesn't support it (yet): https://github.com/node-fetch/node-fetch/blob/master/docs/v3-LIMITS.md