246526 2022-10-14 09:56:01 -0700 [Fetch API] Headers iteration should not happen on cached headers list 2022-10-19 02:00:46 -0700 1 1 1 Unclassified WebKit WebCore Misc. WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 151937 1 rakuco youennf achristensen annevk webkit-bug-importer youennf oldest_to_newest 1905661 0 rakuco 2022-10-14 09:56:01 -0700 See https://github.com/web-platform-tests/wpt/pull/36455 FetchHeaders::Iterator seems to cache a FetchHeaders' keys at the time iteration starts, so if the same instance is modified during iteration not all changes will be visible. 1906037 1 webkit-bug-importer 2022-10-17 00:01:56 -0700 <rdar://problem/101235580> 1906042 2 youennf 2022-10-17 00:50:07 -0700 Pull request: https://github.com/WebKit/WebKit/pull/5437 1906048 3 annevk 2022-10-17 01:38:40 -0700 Raphael, did you happen to check `FormData` and `URLSearchParams` as well? This might benefit from testing in each API with `iterable<>` given how it's implemented. 1906221 4 ews-feeder 2022-10-17 12:06:43 -0700 Committed 255639@main (68f5a2f24c94): <https://commits.webkit.org/255639@main> Reviewed commits have been landed. Closing PR #5437 and removing active labels. 1906548 5 rakuco 2022-10-18 12:02:59 -0700 (In reply to Anne van Kesteren from comment #3) > Raphael, did you happen to check `FormData` and `URLSearchParams` as well? > This might benefit from testing in each API with `iterable<>` given how it's > implemented. URLSearchParams is covered by https://github.com/web-platform-tests/wpt/blob/master/webidl/ecmascript-binding/iterator-invalidation-foreach.html (I actually based the Fetch tests on it). I've submitted https://github.com/web-platform-tests/wpt/pull/36532 to cover FormData. I haven't checked it in depth, but I think all engines implement them correctly because their "value pairs to iterate over" are just their internal name-value lists. Things get trickier with Headers because it's one of the few cases where the value pairs require modification to the internal data structure. AFAICS only a handful of interfaces do that: Headers, MediaKeyStatusMap (possibly), XRHand (also possibly), and StylePropertyMap (it's CSS so I have close to no idea :-). 1906729 6 annevk 2022-10-19 02:00:46 -0700 Thanks Raphael, much appreciated!