233956 2021-12-07 16:14:51 -0800 WebKit thinks that a formatting context root stops fitting in a tiny space, when you give it a negative margin 2022-05-02 12:55:21 -0700 1 1 1 Unclassified WebKit Layout and Rendering Safari 15 Unspecified Unspecified RESOLVED INVALID https://bugs.chromium.org/p/chromium/issues/detail?id=1141209 https://bugzilla.mozilla.org/show_bug.cgi?id=1745310 InRadar P2 Normal --- 1 dholbert webkit-unassigned bfulgham simon.fraser webkit-bug-importer zalan oldest_to_newest 1821261 0 446248 dholbert 2021-12-07 16:14:51 -0800 Created attachment 446248 testcase 1 STR: 1. Load attached testcase. (also available on jsfiddle: https://jsfiddle.net/dholbert/ujphfkqz/ ) EXPECTED RESULTS: Case 1 and Case 2 inside of the testcase should look the same. ACTUAL RESULTS: In "Case 2", the "A B" text is pushed down, for no clear reason. The only difference between Case 1 and Case 2 is: in Case 2, the "A B" element has a *negative margin*. So if anything, it should fit even better; there should be even less reason to push it down. Chrome has the same bug, tracked in https://bugs.chromium.org/p/chromium/issues/detail?id=1141209 . Firefox gives EXPECTED RESULTS. 1821262 1 446249 dholbert 2021-12-07 16:17:16 -0800 Created attachment 446249 testcase 2 (using display:flow-root instead of flex) Note: testcase 1 used flexbox, but as discussed on the chromium bug report, this isn't specific to flexbox; you can reproduce it with 'display:flow-root' as well, for example. Here's a version using 'display: flow-root'. 1821356 2 webkit-bug-importer 2021-12-07 20:29:23 -0800 <rdar://problem/86189973> 1822420 3 dholbert 2021-12-09 16:31:35 -0800 For reference, I filed https://bugzilla.mozilla.org/show_bug.cgi?id=1745310 on the Firefox side, as a place to aggregate webcompat issues that we've run into as a result of this interop issue. 1865922 4 dholbert 2022-05-02 12:55:21 -0700 I've done some more investigation and I actually think the WebKit/Blink behavior makes some sense here, per https://bugzilla.mozilla.org/show_bug.cgi?id=1745310#c9 . And the web apparently depends on it (per the various WebCompat dupes over there). So, we can close this one as INVALID. But while investigating that, I found a WebKit-specific version of this behavior that makes less sense and that I suspect the web does *not* depend on, and I filed that as: https://bugs.webkit.org/show_bug.cgi?id=239976 446248 2021-12-07 16:14:51 -0800 2021-12-07 16:14:51 -0800 testcase 1 test-float.html text/html 893 dholbert PCFET0NUWVBFIGh0bWw+CjxzdHlsZT4KLm91dGVyIHsKICB3aWR0aDogMjAwcHg7CiAgaGVpZ2h0 OiA1MHB4OwogIGJvcmRlcjogMXB4IHNvbGlkIGJsYWNrOwogIG1hcmdpbi1ib3R0b206IDMwcHg7 Cn0KCi5ncmVlZHktZmxvYXQgewogIHdpZHRoOiAxMDAlOwogIGhlaWdodDogNTBweDsKICBmbG9h dDogbGVmdDsKICBiYWNrZ3JvdW5kOiBwaW5rOwp9CgouZmxleCB7CiAgZGlzcGxheTogZmxleDsK fQoKLml0ZW0gewogIC8qIFRoaXMgaXNuJ3QgbmVjZXNzYXJ5IHRvIHRyaWdnZXIgdGhlIGJ1ZywK ICAgKiBidXQgaXQganVzdCBtYWtlcyBpdCBleHRyYS1jbGVhciB0aGF0IHRoZQogICAqIGZsZXgg Y29udGFpbmVyIGNhbiBmaXQgdG8gdGhlIHJpZ2h0IG9mCiAgICogdGhlIGZsb2F0OiAqLwogIHdp ZHRoOiAwOwp9CgoubmVnLW1hcmdpbiB7CiAgbWFyZ2luLXJpZ2h0OiAtMTVweDsKfQo8L3N0eWxl Pgo8Ym9keT4KPGgzPldoZXJlIGRvZXMgdGhlICJBIEIiIHRleHQgZW5kIHVwIGluIHRoZSBjYXNl cyBiZWxvdz88L2gzPgpDYXNlIDE6CjxkaXYgY2xhc3M9Im91dGVyIj4KICA8ZGl2IGNsYXNzPSJn cmVlZHktZmxvYXQiPjwvZGl2PgogIDxkaXYgY2xhc3M9ImZsZXgiPgogICAgPGRpdiBjbGFzcz0i aXRlbSI+CiAgICBBIEIKICAgIDwvZGl2PgogIDwvZGl2Pgo8L2Rpdj4KCkNhc2UgMjogU2FtZSBh cyBhYm92ZSwgYnV0IG5vdyB3aXRoIGEgbmVnYXRpdmUgbWFyZ2luIG9uIHRoZSAiQSBCIiBjb250 YWluZXI6CjxkaXYgY2xhc3M9Im91dGVyIj4KICA8ZGl2IGNsYXNzPSJncmVlZHktZmxvYXQiPjwv ZGl2PgogIDxkaXYgY2xhc3M9ImZsZXggbmVnLW1hcmdpbiI+CiAgICA8ZGl2IGNsYXNzPSJpdGVt Ij4KICAgIEEgQgogICAgPC9kaXY+CiAgPC9kaXY+CjwvZGl2Pgo= 446249 2021-12-07 16:17:16 -0800 2021-12-07 16:17:16 -0800 testcase 2 (using display:flow-root instead of flex) test-with-flow-root.html text/html 918 dholbert PCFET0NUWVBFIGh0bWw+CjxzdHlsZT4KLm91dGVyIHsKICB3aWR0aDogMjAwcHg7CiAgaGVpZ2h0 OiA1MHB4OwogIGJvcmRlcjogMXB4IHNvbGlkIGJsYWNrOwogIG1hcmdpbi1ib3R0b206IDMwcHg7 Cn0KCi5ncmVlZHktZmxvYXQgewogIHdpZHRoOiAxMDAlOwogIGhlaWdodDogNTBweDsKICBmbG9h dDogbGVmdDsKICBiYWNrZ3JvdW5kOiBwaW5rOwp9CgouZmxvdy1yb290IHsKICBkaXNwbGF5OiBm bG93LXJvb3Q7Cn0KCi5pdGVtIHsKICAvKiBUaGlzIGlzbid0IG5lY2Vzc2FyeSB0byB0cmlnZ2Vy IHRoZSBidWcsCiAgICogYnV0IGl0IGp1c3QgbWFrZXMgaXQgZXh0cmEtY2xlYXIgdGhhdCB0aGUK ICAgKiBmbG93LXJvb3QgY29udGFpbmVyIGNhbiBmaXQgdG8gdGhlIHJpZ2h0IG9mCiAgICogdGhl IGZsb2F0OiAqLwogIHdpZHRoOiAwOwp9CgoubmVnLW1hcmdpbiB7CiAgbWFyZ2luLXJpZ2h0OiAt MTVweDsKfQo8L3N0eWxlPgo8Ym9keT4KPGgzPldoZXJlIGRvZXMgdGhlICJBIEIiIHRleHQgZW5k IHVwIGluIHRoZSBjYXNlcyBiZWxvdz88L2gzPgpDYXNlIDE6CjxkaXYgY2xhc3M9Im91dGVyIj4K ICA8ZGl2IGNsYXNzPSJncmVlZHktZmxvYXQiPjwvZGl2PgogIDxkaXYgY2xhc3M9ImZsb3ctcm9v dCI+CiAgICA8ZGl2IGNsYXNzPSJpdGVtIj4KICAgIEEgQgogICAgPC9kaXY+CiAgPC9kaXY+Cjwv ZGl2PgoKQ2FzZSAyOiBTYW1lIGFzIGFib3ZlLCBidXQgbm93IHdpdGggYSBuZWdhdGl2ZSBtYXJn aW4gb24gdGhlICJBIEIiIGNvbnRhaW5lcjoKPGRpdiBjbGFzcz0ib3V0ZXIiPgogIDxkaXYgY2xh c3M9ImdyZWVkeS1mbG9hdCI+PC9kaXY+CiAgPGRpdiBjbGFzcz0iZmxvdy1yb290IG5lZy1tYXJn aW4iPgogICAgPGRpdiBjbGFzcz0iaXRlbSI+CiAgICBBIEIKICAgIDwvZGl2PgogIDwvZGl2Pgo8 L2Rpdj4K