WPT failure: DOMContentLoaded fires before a task that is queued from inside a defer script fires

[pshaughn]

https://wpt.fyi/results/html/syntax/parsing/DOMContentLoaded-defer.html?label=experimental&label=master&aligned is solid red at this time; Servo is failing just like everyone else. This looks like it's involving full tasks rather than microtasks, so it's not redundant with #25016.

[pwnorbitals]

How could one help with this issue ? I'm not sure how to get started

[jdm]

The test in question is https://github.com/servo/servo/blob/master/tests/wpt/web-platform-tests/html/syntax/parsing/DOMContentLoaded-defer.html (which can be run with ./mach test-wpt tests/wpt/web-platform-tests/html/syntax/parsing/DOMContentLoaded-defer.html). We currently mark this test as an expected failure, but so does every other browser. This suggests that either the actual test does not match the specification, or that all browsers do not implement the specification and (presumably) the specification should be amended to match actual behaviour. We should really file an issue upstream in https://github.com/web-platform-tests/wpt about this.

[pwnorbitals]

Thanks for the guidance.
An issue already exists over there : web-platform-tests/wpt#4267
It had no progress for 4 years, so I will ping the issue there to see if any progress can be made