326182 2026-10-03 00:28:23 -0700 moveBefore() leaves selectors that depend on the child list stale 2026-10-07 17:23:17 -0700 1 1 1 Unclassified WebKit DOM WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=317287 InRadar P2 Normal --- 281223 1 annevk lwarlow lwarlow webkit-bug-importer oldest_to_newest 2258179 0 481650 annevk 2026-10-03 00:28:23 -0700 Created attachment 481650 test ContainerNode::moveBefore() runs no Style::ChildChangeInvalidation, for either the old parent or the new one. insertBefore(), appendChild() and removeChild() all wrap the DOM change in one. Since 315405@main, Node::movingSteps() invalidates the moved subtree. But nothing invalidates the parents or their other children, so every selector that depends on the child list keeps its old result after a move. The attached test moves an element with moveBefore() and checks the result. With ?append it uses append() instead (and passes). This is probably also why dom/nodes/moveBefore/focus-within.html fails ":focus-within should be eventually up to date when moving to a subtree that would become inert via style". The inertness there comes from :has(button) on the new parent. moveBefore() already builds both child changes, with makeChildChangeForMoveRemoval() and makeChildChangeForMoveInsertion(), but only passes them to childrenChanged(). Running a Style::ChildChangeInvalidation around each half of the move would fix this, with one catch. ChildChange::isInsertion() returns false for ElementMovedInto, TextMovedInto and NonContentsChildMovedInto. ChildChangeInvalidation relies on it to choose before- or after-change invalidation, and for :empty. Other childrenChanged() overrides read isInsertion() too, so style needs its own answer for the move types rather than a change to isInsertion(). Bug 317287 is about doing less work for the moved subtree itself, which is a separate question. There is no WPT for this yet; one in dom/nodes/moveBefore/ along the lines of the attached test would cover it. 2260092 1 lwarlow 2026-10-07 07:48:29 -0700 Pull request: https://github.com/WebKit/WebKit/pull/76188 2260423 2 ews-feeder 2026-10-07 17:22:24 -0700 Committed 323044@main (6839061acafd): <https://commits.webkit.org/323044@main> Reviewed commits have been landed. Closing PR #76188 and removing active labels. 2260424 3 webkit-bug-importer 2026-10-07 17:23:17 -0700 <rdar://problem/189461850> 481650 2026-10-03 00:28:23 -0700 2026-10-03 00:28:23 -0700 test movebefore-child-change-invalidation.html text/html 1953 annevk PCFET0NUWVBFIGh0bWw+CjxzdHlsZT4KLmhhc0NoaWxkOmhhcyg+IC5tYXJrZWQpIHsgY29sb3I6 IGdyZWVuOyB9Ci5lbXB0eUNoZWNrOmVtcHR5IHsgY29sb3I6IGdyZWVuOyB9Ci5maXJzdENoZWNr ID4gOmZpcnN0LWNoaWxkIHsgY29sb3I6IGdyZWVuOyB9Ci5udGhDaGVjayA+IDpudGgtY2hpbGQo MikgeyBjb2xvcjogZ3JlZW47IH0KLnNpYmxpbmdDaGVjayAuYSArIC5iIHsgY29sb3I6IGdyZWVu OyB9Cjwvc3R5bGU+CjxkaXYgaWQ9aGFzU291cmNlIGNsYXNzPWhhc0NoaWxkPjxzcGFuIGlkPWhh c01vdmVkIGNsYXNzPW1hcmtlZD5tb3ZlZDwvc3Bhbj48L2Rpdj4KPGRpdiBpZD1oYXNEZXN0aW5h dGlvbiBjbGFzcz1oYXNDaGlsZD48L2Rpdj4KPGRpdiBpZD1lbXB0eVNvdXJjZSBjbGFzcz1lbXB0 eUNoZWNrPjxzcGFuIGlkPWVtcHR5TW92ZWQ+bW92ZWQ8L3NwYW4+PC9kaXY+CjxkaXYgaWQ9ZW1w dHlEZXN0aW5hdGlvbj48L2Rpdj4KPGRpdiBjbGFzcz1maXJzdENoZWNrPjxzcGFuIGlkPWZpcnN0 TW92ZWQ+Zmlyc3Q8L3NwYW4+PHNwYW4gaWQ9c2Vjb25kPnNlY29uZDwvc3Bhbj48L2Rpdj4KPGRp diBpZD1maXJzdERlc3RpbmF0aW9uPjwvZGl2Pgo8ZGl2IGNsYXNzPW50aENoZWNrPjxzcGFuIGlk PW50aE1vdmVkPjE8L3NwYW4+PHNwYW4+Mjwvc3Bhbj48c3BhbiBpZD10aGlyZD4zPC9zcGFuPjwv ZGl2Pgo8ZGl2IGlkPW50aERlc3RpbmF0aW9uPjwvZGl2Pgo8ZGl2IGNsYXNzPXNpYmxpbmdDaGVj az48c3BhbiBpZD1hTW92ZWQgY2xhc3M9YT5hPC9zcGFuPjxzcGFuIGlkPWIgY2xhc3M9Yj5iPC9z cGFuPjwvZGl2Pgo8ZGl2IGlkPXNpYmxpbmdEZXN0aW5hdGlvbj48L2Rpdj4KPHByZSBpZD1sb2c+ PC9wcmU+CjxzY3JpcHQ+CmlmICh3aW5kb3cudGVzdFJ1bm5lcikKICAgIHRlc3RSdW5uZXIuZHVt cEFzVGV4dCgpOwpjb25zdCBpc0dyZWVuID0gZWxlbWVudCA9PiBnZXRDb21wdXRlZFN0eWxlKGVs ZW1lbnQpLmNvbG9yID09ICJyZ2IoMCwgMTI4LCAwKSI7CmNvbnN0IG1vdmUgPSBuZXcgVVJMU2Vh cmNoUGFyYW1zKGxvY2F0aW9uLnNlYXJjaCkuaGFzKCJhcHBlbmQiKQogICAgPyAocGFyZW50LCBj aGlsZCkgPT4gcGFyZW50LmFwcGVuZChjaGlsZCkKICAgIDogKHBhcmVudCwgY2hpbGQpID0+IHBh cmVudC5tb3ZlQmVmb3JlKGNoaWxkLCBudWxsKTsKCmZvciAoY29uc3QgZWxlbWVudCBvZiBkb2N1 bWVudC5xdWVyeVNlbGVjdG9yQWxsKCJkaXYsIHNwYW4iKSkKICAgIGdldENvbXB1dGVkU3R5bGUo ZWxlbWVudCkuY29sb3I7Cgptb3ZlKGhhc0Rlc3RpbmF0aW9uLCBoYXNNb3ZlZCk7Cm1vdmUoZW1w dHlEZXN0aW5hdGlvbiwgZW1wdHlNb3ZlZCk7Cm1vdmUoZmlyc3REZXN0aW5hdGlvbiwgZmlyc3RN b3ZlZCk7Cm1vdmUobnRoRGVzdGluYXRpb24sIG50aE1vdmVkKTsKbW92ZShzaWJsaW5nRGVzdGlu YXRpb24sIGFNb3ZlZCk7Cgpsb2cudGV4dENvbnRlbnQgPSBbCiAgICBgOmhhcyg+IC5tYXJrZWQp IG9uIHRoZSBvbGQgcGFyZW50OiAke2lzR3JlZW4oaGFzU291cmNlKSA/ICJGQUlMIiA6ICJQQVNT In1gLAogICAgYDpoYXMoPiAubWFya2VkKSBvbiB0aGUgbmV3IHBhcmVudDogJHtpc0dyZWVuKGhh c0Rlc3RpbmF0aW9uKSA/ICJQQVNTIiA6ICJGQUlMIn1gLAogICAgYDplbXB0eSBvbiB0aGUgb2xk IHBhcmVudDogJHtpc0dyZWVuKGVtcHR5U291cmNlKSA/ICJQQVNTIiA6ICJGQUlMIn1gLAogICAg YDpmaXJzdC1jaGlsZCBvbiB0aGUgbmV4dCBzaWJsaW5nOiAke2lzR3JlZW4oc2Vjb25kKSA/ICJQ QVNTIiA6ICJGQUlMIn1gLAogICAgYDpudGgtY2hpbGQoMikgb24gYSBsYXRlciBzaWJsaW5nOiAk e2lzR3JlZW4odGhpcmQpID8gIlBBU1MiIDogIkZBSUwifWAsCiAgICBgLmEgKyAuYiBvbiB0aGUg bmV4dCBzaWJsaW5nOiAke2lzR3JlZW4oYikgPyAiRkFJTCIgOiAiUEFTUyJ9YCwKXS5qb2luKCJc biIpOwo8L3NjcmlwdD4K