240128 2022-05-05 10:57:10 -0700 WebKit improperly overlaps a BFC with a float, with certain margin values 2022-05-12 10:58:12 -0700 1 1 1 Unclassified WebKit Layout and Rendering Safari 15 Unspecified Unspecified NEW https://bugs.chromium.org/p/chromium/issues/detail?id=1322774 https://bugs.webkit.org/show_bug.cgi?id=239976 InRadar P2 Normal --- 1 dholbert webkit-unassigned bfulgham simon.fraser webkit-bug-importer zalan oldest_to_newest 1866915 0 458892 dholbert 2022-05-05 10:57:10 -0700 Created attachment 458892 testcase 1 STR: 1. Load attached testcase. EXPECTED RESULTS: The blue area and the fuchsia area should **not be overlapping**. ACTUAL RESULTS: The blue bordered area overlaps the fuchsia area. There are various pieces of CSS Float layout that are vague or undefined, but one clear requirement is (emphasis added by me): > The border box of [...] an element in the normal flow that establishes a new block formatting context [...] **must not overlap the margin box of any floats in the same block formatting context as the element itself.** If necessary, implementations should clear the said element by placing it below any preceding floats, but may place it adjacent to such floats if there is sufficient space. https://www.w3.org/TR/CSS21/visuren.html#floats WebKit is violating this requirement here. Chromium/Blink has the same bug, which is filed as https://bugs.chromium.org/p/chromium/issues/detail?id=1322774 Firefox gives EXPECTED RESULTS. 1868481 1 webkit-bug-importer 2022-05-12 10:58:12 -0700 <rdar://problem/93187697> 458892 2022-05-05 10:57:10 -0700 2022-05-05 10:57:10 -0700 testcase 1 test.html text/html 445 dholbert PCFET0NUWVBFIGh0bWw+CjxzdHlsZT4KLmNvbnRhaW5lciB7CiAgd2lkdGg6IDEwMHB4OwogIGhl aWdodDogNDBweDsKICBib3JkZXI6IDFweCBzb2xpZCBncmF5Owp9CgouZmxvYXQgewogIGZsb2F0 OiByaWdodDsKICB3aWR0aDogNTBweDsKICBoZWlnaHQ6IDhweDsKICBiYWNrZ3JvdW5kOiBmdWNo c2lhOwogIGJvcmRlcjogMXB4IHNvbGlkIHB1cnBsZTsKICBtYXJnaW46IDNweDsKfQoKLmJmYyB7 CiAgd2lkdGg6IDMwcHg7CiAgaGVpZ2h0OiAxNXB4OwogIGRpc3BsYXk6IGZsb3ctcm9vdDsKICBi YWNrZ3JvdW5kOiBhcXVhOwogIGJvcmRlcjogMXB4IHNvbGlkIGJsdWU7CiAgbWFyZ2luLWxlZnQ6 IDYwcHg7Cn0KPC9zdHlsZT4KPGRpdiBjbGFzcz0iY29udGFpbmVyIj4KICA8ZGl2IGNsYXNzPSJm bG9hdCI+PC9kaXY+CiAgPGRpdiBjbGFzcz0iYmZjIj48L2Rpdj4KPC9kaXY+Cg==