198543 2019-06-04 14:16:01 -0700 [css-text] line-break: anywhere takes chars of zero-width related classes as forced breaks 2025-12-11 23:10:12 -0800 1 1 1 Unclassified WebKit Text WebKit Nightly Build Unspecified Unspecified RESOLVED CONFIGURATION CHANGED https://bugs.webkit.org/show_bug.cgi?id=196169 P2 Normal --- 1 jfernandez webkit-unassigned ahmad.saleem792 jfernandez karlcow mmaxfield oldest_to_newest 1541732 0 371331 jfernandez 2019-06-04 14:16:01 -0700 Created attachment 371331 Test case to reproduce the issue What steps will reproduce the problem? (1) Load the attached test case What is the expected result? No char is sick out from the green box; all the zero-width chars are ignored and should not affect the height of the line (expected.png) What happens instead? The 3 zero-width class chars are used as forced break points, affecting the height of the line, which sicks out below the green box (actual.png) 1541735 1 371333 jfernandez 2019-06-04 14:23:48 -0700 Created attachment 371333 Actual result 1541736 2 371334 jfernandez 2019-06-04 14:24:07 -0700 Created attachment 371334 Expected result 1541737 3 jfernandez 2019-06-04 14:24:56 -0700 This issue is only reproducible in Mac and iOs platforms, so that means that the bug is in the SimpleLineLayout codepath. 1542335 4 371482 jfernandez 2019-06-06 02:43:42 -0700 Created attachment 371482 Test case to reproduce the issue 1542336 5 371483 jfernandez 2019-06-06 02:44:07 -0700 Created attachment 371483 Actual result 1542354 6 jfernandez 2019-06-06 04:59:39 -0700 After debugging the test case, I've got new information regarding this issue. First of all, this is not affecting the SimpleLineLayout codepath at all, which is not executed if the value of the line-break property is different than 'auto'. Hence, the bug is affecting the BreakingContext path. Additionally, since other ports also use the BreakingContext path, why this bug is not reproducible in WebKitGtk+ ? The reason seems to be that the root cause of this issue is the #196169 bug (maybe duplicated ?) Debugging the attached test case, I've got the following data: * Mac platform - availableWidth (1ch) = 7.796875 - charWidth = 7.80126953 * Gtk platform - availableWidth (1ch) = 8 - charWidth = 8 The consequence of having a charWidth bigger than the availableWidth is that the line breaking logic may have to break just after the char, even that theoretically the single char should fit. Hence, the problem is not related to the line-break: anywhere feature, but more with how WebKit deals with the monospace font and the 'ch' sizing unit. 2165334 7 ahmad.saleem792 2025-12-11 23:10:12 -0800 I am not able to reproduce this on Safari 26.1. Marking this as `Configuration Changed`, please reopen if it is still reproducing. Thanks1 371331 2019-06-04 14:16:01 -0700 2019-06-06 02:43:42 -0700 Test case to reproduce the issue test.html text/html 372 jfernandez PCFET0NUWVBFIGh0bWw+CjxodG1sIGxhbmc9ZW4+CjxtZXRhIGNoYXJzZXQ9InV0Zi04Ij4KPHN0 eWxlPgojZ3JlZW4gewogIHBvc2l0aW9uOiBhYnNvbHV0ZTsKICBiYWNrZ3JvdW5kOiBncmVlbjsK ICBmb250LWZhbWlseTogbW9ub3NwYWNlOwogIHdpZHRoOiAxY2g7CiAgaGVpZ2h0OiAxMGVtOwp9 CiN0ZXN0IHsKICBsaW5lLWhlaWdodDogMTsKICBjb2xvcjogcmVkOwogIGZvbnQtZmFtaWx5OiBt b25vc3BhY2U7CiAgd2lkdGg6IDFjaDsKCiAgbGluZS1icmVhazogYW55d2hlcmU7Cn0KPC9zdHls ZT4KPGRpdiBpZD1ncmVlbj48L2Rpdj4KPGRpdiBpZD10ZXN0PmEmbmJzcDthJiN4ZmVmZjthJiN4 MjA2MDthJiN4MjAwZDthOyYjMjAwYjs8L2Rpdj4K 371333 2019-06-04 14:23:48 -0700 2019-06-06 02:44:07 -0700 Actual result actual.png image/png 893 jfernandez iVBORw0KGgoAAAANSUhEUgAAABgAAACiCAYAAABbJg3rAAAABmJLR0QA/wD/AP+gvaeTAAAACXBI WXMAAC4jAAAuIwF4pT92AAAAB3RJTUUH4wYEFRcdIE4orwAAABl0RVh0Q29tbWVudABDcmVhdGVk IHdpdGggR0lNUFeBDhcAAALlSURBVGje7dtbiE1RHMfx79p7n7NHTAaNHMYtJNdcikQ8uCfURMiD y4M8UF48KG+U4lHK7U0pUeJBiESYqCHM5DJmjENoZhzjMnNue6+/h1PzJDPM3iH/9bp2+9N//9f+ 7fWwNjPnzJU4h0PM498HvO4u2HFuM+++vP3h3K4Fe5g/ZmHvgGct9TRnGn8415799B/0QAEFFFBA AQUUUEABBRRQQAEFFFBAAQUUUEABBRRQQAEFFFBAAQUUUEABBRRQQAEFFFBAAQX+KEBPDnYH125L bstuCZ++FJvLi1gb7cFuMzyFKS+nsGs/wdlLSDbX4wK6PbVs0++QzGfcdStw2jJIY5rw5n3c6RMx QyojAGrrCI6cQjqzOGNGgLXIlVvIhlUkNlX3vsnO7GmYkcOgX1+8zWtwF83DVKWQ1o/RPCJn6GDM 8BQ8b8I2NCNNadzqpZiBFREv044stimNffEKZ8p4nBmToqmgayWNG0Vi5yZsQzO2tg78JN7yBRFU UAzgWyeEIcZP4oyqwtY8wNa/iKaCwsFjBKcvIEFI5+RlpWr6+CT27ozuTdZfNH7+Jje+Jrh8C2n5 GBPQ8JrivsOED+vjAdxZUyGbh/avvwV0u0zNwAooSxLeqCE4fxXyebxVi0px0b88uiYHpy/ijK7C mTCWwqHjFE+eQQrF6KLC27qW5IHdSEcW/CS2tg5531JK2l4BImAFsjmkNYMUCkhHFpNIgGMi+OA8 foa0ZQiv3aHo+4i12KcvSWxcjakc1HtAPrTiVS/DpCqR9y0QWhLb1uMunocp8yPMImvFBkFpV/EL o8dNxhiM64Lr6tbxDwFSDJC2T8i3jngA+6CO/Pa9BCfOIPlCdGHXBTSlsU+eYwb0h84c+MloAW/J fEyZjxk5DFNRHkMPbEh4vQZ7/zEShDH04N6j0vYl0w6OEwNw/S6mKoW3YSXGjQN49QZvzfJu8/+3 m1x2/mhXJsUC/OqNNez+HuA7/5dnUHePTQQAAAAASUVORK5CYII= 371334 2019-06-04 14:24:07 -0700 2019-06-04 14:24:07 -0700 Expected result expected.png image/png 228 jfernandez iVBORw0KGgoAAAANSUhEUgAAAA0AAACQCAYAAADTE+HhAAAABmJLR0QA/wD/AP+gvaeTAAAACXBI WXMAAC4jAAAuIwF4pT92AAAAB3RJTUUH4wYEFRUT9cBnKgAAABl0RVh0Q29tbWVudABDcmVhdGVk IHdpdGggR0lNUFeBDhcAAABMSURBVFjD7dkhDsAwDAPAZuq/q77cQ6OVOrROZxTgI6GuJGmbudqL /BH156hZy2JGfA+CIAiCIAiCIAiCIAiCIAiCIAj6Dio74RHoBr4tDBmRjYYPAAAAAElFTkSuQmCC 371482 2019-06-06 02:43:42 -0700 2019-06-06 02:43:42 -0700 Test case to reproduce the issue line-break-anywhere-issue.html text/html 371 jfernandez PCFET0NUWVBFIGh0bWw+CjxodG1sIGxhbmc9ZW4+CjxtZXRhIGNoYXJzZXQ9InV0Zi04Ij4KPHN0 eWxlPgojZ3JlZW4gewogIHBvc2l0aW9uOiBhYnNvbHV0ZTsKICBiYWNrZ3JvdW5kOiBncmVlbjsK ICBmb250LWZhbWlseTogbW9ub3NwYWNlOwogIHdpZHRoOiAxY2g7CiAgaGVpZ2h0OiA4ZW07Cn0K I3Rlc3QgewogIGxpbmUtaGVpZ2h0OiAxOwogIGNvbG9yOiByZWQ7CiAgZm9udC1mYW1pbHk6IG1v bm9zcGFjZTsKICB3aWR0aDogMWNoOwoKICBsaW5lLWJyZWFrOiBhbnl3aGVyZTsKfQo8L3N0eWxl Pgo8ZGl2IGlkPWdyZWVuPjwvZGl2Pgo8ZGl2IGlkPXRlc3Q+YSZuYnNwO2EmI3hmZWZmO2EmI3gy MDYwO2EmI3gyMDBkO2EmI3gyMDBiOzwvZGl2Pgo= 371483 2019-06-06 02:44:07 -0700 2019-06-06 02:44:07 -0700 Actual result actual.png image/png 510 jfernandez iVBORw0KGgoAAAANSUhEUgAAABcAAAB1CAYAAAClFnrxAAAABmJLR0QA/wD/AP+gvaeTAAAACXBI WXMAAC4jAAAuIwF4pT92AAAAB3RJTUUH4wYGCSsCYYDOOgAAABl0RVh0Q29tbWVudABDcmVhdGVk IHdpdGggR0lNUFeBDhcAAAFmSURBVGje7dqxLwNhGAbw58612ok0FQmRCB3FwCQSKkjEYJOIqYvN 0MFiM/AHiD/BwGAQBolEUumEgYVYJIaSpuRa9NSdu3sNEpaLcr0OledNbnq/++XL891704fBoWGp V6moYzUurlVbsLiTwv1zzrOXHl3GSO+4f/y6cIlb/cazV6oU/2nmxIkTJ06cOHHixIkTJ06cOHHi xIkTJ06cOHHixIkTJ06cOHHinlX1rsVYYhKFcr9nr7Ol6+eXeTPHV+ZfJfL5AICqBrdzJ3OCSnIe rz1JVKZSsA+OA4xFBNrsNJq319E00Ad7cxfyoAcQiyuQRx3u6QXsrT1I8QlqRzvkLg+lLVbbzqVs wEqvQkl0I7yxAm1hDohGANf9PgPfuGVBibdC9BKc/SM4h1lILg/n/AryYtQWixqPIbS2BCd7BryZ 0GYmIGUDSjQCvNvBTKhrWuKa5p8m9NffuRIO8X9OvFHxD7uXbgGqtENyAAAAAElFTkSuQmCC