225809 2021-05-14 08:28:07 -0700 [LFC][IFC] line-height incorrectly triggers scrollable overflow 2021-05-14 13:55:58 -0700 1 1 1 Unclassified WebKit Layout and Rendering WebKit Nightly Build Unspecified Unspecified NEW InRadar P2 Normal --- 1 zalan webkit-unassigned bfulgham simon.fraser webkit-bug-importer zalan oldest_to_newest 1760077 0 428623 zalan 2021-05-14 08:28:07 -0700 Created attachment 428623 test case ssia 1760078 1 webkit-bug-importer 2021-05-14 08:28:25 -0700 <rdar://problem/78017815> 1760079 2 webkit-bug-importer 2021-05-14 08:28:45 -0700 <rdar://problem/78017824> 1760088 3 zalan 2021-05-14 08:37:57 -0700 see http://wpt.live/css/CSS2/linebox/scrollable-overflow.tentative.html 1760169 4 zalan 2021-05-14 12:42:14 -0700 According to the CSS Overflow Module Level 3 (https://www.w3.org/TR/css-overflow-3/#scrollable) and CSS Inline Layout Module Level 3 (https://www.w3.org/TR/css-inline-3/#line-layout) this looks like a progression. CSS Overflow Module says: "... The scrollable overflow area is the union of: ... - all line boxes directly contained by the box .." while CSS Inline Layout Module says: ".. The line box’s logical height is calculated to exactly include the aligned layout bounds of all its inline-level boxes. .." where the layout bounds are computed by taking the (non-normal) line-height into account ("When its computed line-height is not normal, its layout bounds are derived solely from metrics of its first available font (ignoring glyphs from other fonts), and leading is used to adjust the effective A and D to add up to the used line-height." so it looks like the "line-height" here should affect the scrollable overflow area and Safari should produce a scrollbar for it. It also matches Firefox(88.0.1) behavior. I'd say this is a progression but according to https://bugs.chromium.org/p/chromium/issues/detail?id=996847, this is not what's expected. 1760197 5 zalan 2021-05-14 13:55:58 -0700 Blink's test reduction https://bugs.chromium.org/p/chromium/issues/attachmentText?aid=409419 428623 2021-05-14 08:28:07 -0700 2021-05-14 08:28:07 -0700 test case line-height-overflow.html text/html 332 zalan PCFET0NUWVBFIGh0bWw+CjxkaXYgaWQ9c2Nyb2xsYWJsZSBzdHlsZT0ib3ZlcmZsb3c6IGF1dG87 IHdpZHRoOiAxMDBweDsgaGVpZ2h0OiAxMDBweDsgYmFja2dyb3VuZC1jb2xvcjogcmVkOyI+PGRp diBzdHlsZT0ibGluZS1oZWlnaHQ6IDEyMHB4OyBoZWlnaHQ6IDEwMHB4OyBiYWNrZ3JvdW5kOiBn cmVlbjsiPjxkaXYgc3R5bGU9ImRpc3BsYXk6IGlubGluZS1ibG9jazsgd2lkdGg6IDFweDsgaGVp Z2h0OiAxcHg7Ij48L2Rpdj48L2Rpdj48L2Rpdj4KPCEtLSBQQVNTIGlmIGFsbCBncmVlbiAtLT4K PHNjcmlwdD4Kc2Nyb2xsYWJsZS5zY3JvbGxUbygwLCAyMCk7Cjwvc2NyaXB0Pgo=