215771 2020-08-24 09:59:28 -0700 Unhandled Promise Rejection: Abort Error: Fetch is aborted 2023-03-23 07:53:15 -0700 1 1 1 Unclassified WebKit New Bugs Safari 13 All macOS 10.15 RESOLVED CONFIGURATION CHANGED InRadar P1 Normal --- 1 sobue webkit-unassigned anna.peery asheem.mamoowala webkit-bug-importer youennf oldest_to_newest 1682358 0 sobue 2020-08-24 09:59:28 -0700 Lots of `Unhandled Promise Rejection: Abort Error: Fetch is aborted` error is being displayed in console, when network is disconnected while data from `ReadableStream` is being read. The sample code below will abort stream data reading after 1 second. Chrome browser does not throw an error and ends stream reading gracefully, however Safari and WkWebView threw lots of error in console. -- ``` const url = 'https://...'; // URL which takes more than 1 second to download function test(url) { const abortController = new AbortController(); window.setTimeout(() => { abortController.abort(); }, 1000); window.fetch(url, { signal: abortController.signal }).then(response => { const reader = response.body.getReader(); reader.read().then(function processData({ value, done}) { if (done) { return; } return reader.read().then(processData); }) .catch(error => console.error('reader error handled gracefully', error)); }); } test(url); ``` 1682362 1 sobue 2020-08-24 10:07:15 -0700 This line of the code seems throwing those errors. https://github.com/WebKit/webkit/blob/950143da027e80924b4bb86defa8a3f21fd3fb1e/Source/WebCore/Modules/streams/ReadableStreamInternals.js#L302 I guess there are lots of internal requests being queued to buffer incoming data for efficient reading. Those requests being cancelled should not be revealed to consumer in console pane. 1682588 2 youennf 2020-08-24 23:37:51 -0700 Right, we should add @promiseFlagsIsHandled to the promises. In general, we should update the ReadableStream implementation up to spec. 1684160 3 webkit-bug-importer 2020-08-31 10:00:32 -0700 <rdar://problem/68082772> 1727958 4 asheem.mamoowala 2021-02-10 21:43:26 -0800 This is a problem in Mapbox-GL-JS that is being faced by a number of users of the library. Reference: https://github.com/mapbox/mapbox-gl-js/issues/8480 Whether using a nested promise or a chained promise, this error is logged to the console when a fetch request is cancelled while reading the response data. Link to the code in question: https://github.com/mapbox/mapbox-gl-js/blob/0102e52123fc66df98853620ced6e0e3195fa9a4/src/util/ajax.js#L144-L157 This problem affects our customers who are using logged errors for production applications, and have to handle a large number of these spurious errors. 1921403 5 anna.peery 2022-12-22 09:56:38 -0800 Any update on this? I opened a new ticket to bump up this issue as it seems to be a continued problem: https://bugs.webkit.org/show_bug.cgi?id=249784 Thanks! 1921464 6 ap 2022-12-22 13:08:39 -0800 *** Bug 249784 has been marked as a duplicate of this bug. *** 1943363 7 youennf 2023-03-23 07:53:15 -0700 I cannot reproduce with the snippet, closing as configuration changed. I'll fix https://bugs.webkit.org/show_bug.cgi?id=251463 which is still an issue.