457675 2022-08-09 12:28:17 +0000 AboutItem freezes with certain font/content combinations 2022-08-16 16:01:11 +0000 1 1 3 Frameworks and Libraries frameworks-kirigami general Master Kubuntu Linux RESOLVED FIXED NOR normal Not decided 1 kbugs kdelibs-bugs-null kbugs nate notmart https://invent.kde.org/frameworks/kirigami/commit/2676403e803d84e4963fa4e5f3779012e001bf24 5.98 0 oldest_to_newest 2144557 0 151192 kbugs 2022-08-09 12:28:17 +0000 Created attachment 151192 qml example SUMMARY Certain font settings cause Kirigami::AboutItem (and AboutPage) to enter an infinite loop when the homepage URL is the widest thing in the form. STEPS TO REPRODUCE 1. run the attached file with qmlscene OBSERVED RESULT Test application freezes with repeated warnings: Qt Quick Layouts: Polish loop detected. Aborting after two iterations. file:///home/connor/Projects/kde/usr/lib/x86_64-linux-gnu/qml/org/kde/kirigami.2/AboutItem.qml:150:5: QML FormLayout (parent or ancestor of QQuickLayoutAttached): Binding loop detected for property "preferredHeight" file:///home/connor/Projects/kde/usr/lib/x86_64-linux-gnu/qml/org/kde/kirigami.2/AboutItem.qml:150:5: QML FormLayout (parent or ancestor of QQuickLayoutAttached): Binding loop detected for property "preferredHeight" file:///home/connor/Projects/kde/usr/lib/x86_64-linux-gnu/qml/org/kde/kirigami.2/AboutItem.qml:150:5: QML FormLayout: Binding loop detected for property "implicitHeight" SOFTWARE/OS VERSIONS Linux/KDE Plasma: Kubuntu 20.04 KDE Plasma Version: 5.24 KDE Frameworks Version: master Qt Version: 5.15.3 2144641 1 nate 2022-08-09 19:26:58 +0000 Fixed in Frameworks 5.94; IIRC Kubuntu has 5.92, right? *** This bug has been marked as a duplicate of bug 447958 *** 2144682 2 kbugs 2022-08-09 21:59:54 +0000 This looks similar to that discover bug, but I don't think it's actually a duplicate: that one was working around binding loops with the scroll bar in AboutPage. My attached example just has a raw AboutItem in a window with no pages or scroll bars in sight. (It happens with AboutPage too, it's just not necessary to trigger the bug) In any case, it's not fixed: I tested it against a source build of master, and I can also reproduce it in the current flatpak runtime e.g. flatpak run --socket=x11 --device=dri --filesystem=home org.kde.Sdk [📦 org.kde.Sdk ~]$ qmlscene about-page-freeze.qml 2144827 3 nate 2022-08-10 14:33:35 +0000 Darn. 2144838 4 151226 kbugs 2022-08-10 15:00:13 +0000 Created attachment 151226 formlayout-freeze I dug into the AboutItem QML and it seems like all that's necessary to recreate the freeze is FormLayout+UrlButton. I've attached an even more minimal example. 2144887 5 nate 2022-08-10 17:40:30 +0000 What font and/or font size are necessary to reproduce the bug? That qml file doesn't freeze for me (Wayland, 200% scale, 11pt Noto Sans font). 2144908 6 kbugs 2022-08-10 17:57:10 +0000 That QML file explicitly sets Ubuntu 10 pt on the ApplicationWindow, so it shouldn't depend on your font settings, although it does depend on having that font installed. I normally use kwin-wayland @ 100%, but it also happens in an X session. It takes some trial and error to find specific combinations of font+size+text that trigger the issue for me, but when I find one it freezes consistently. 2144944 7 151234 kbugs 2022-08-10 21:33:25 +0000 Created attachment 151234 formlayout-freeze-notosans Here's a case that freezes for me with Noto Sans. It's interesting that Noto Sans is much less prone to this issue than the Ubuntu font. I could find cases for Ubuntu by just randomly typing stuff; with Noto Sans I had to actually write a script to find one. 2145160 8 nate 2022-08-11 17:25:13 +0000 Can confirm the freeze with that file. 2146143 9 nate 2022-08-16 16:01:11 +0000 Git commit 2676403e803d84e4963fa4e5f3779012e001bf24 by Nate Graham, on behalf of Connor Carney. Committed on 16/08/2022 at 16:01. Pushed by ngraham into branch 'master'. FormLayout: Explicitly round up implicit sizes The implicit size of an item may not be an integral number of pixels. GridLayout internally `ceil`s the implicitHeight and implicitWidth properties, but not the Layout.* attached properties, so we need to call Math.ceil ourselves whenever we set a Layout property based on the implicit size. If a non-integral layout parameter has a fractional part <0.5 then the layout engine will end up rounding it down to a pixel-aligned value that is not quite large enough to fit the contents (see included test case). For word-wrapped text, the slightly-too-small size causes the text to inappropriately wrap. If the implicit size of the wrapped text gets rounded differently it causes an infinite loop in the layout. This changes the behavior of existing clients: items with non-integral implicit widths will sometimes lay out exactly 1 pixel larger. This won't be an actual problem for existing code. Implicit sizes already get rounded up about half the time and layouts should already be prepared for that. FIXED-IN: 5.98 M +1 -0 autotests/CMakeLists.txt A +50 -0 autotests/tst_formlayout.qml * M +2 -2 src/controls/FormLayout.qml The files marked with a * at the end have a non valid license. Please read: https://community.kde.org/Policies/Licensing_Policy and use the headers which are listed at that page. https://invent.kde.org/frameworks/kirigami/commit/2676403e803d84e4963fa4e5f3779012e001bf24 151192 2022-08-09 12:28:17 +0000 2022-08-09 12:28:17 +0000 qml example about-page-freeze.qml text/x-qml 812 kbugs aW1wb3J0IG9yZy5rZGUua2lyaWdhbWkgMi4xOQoKQXBwbGljYXRpb25XaW5kb3cgewogICAgZm9u dC5mYW1pbHk6ICJVYnVudHUiCiAgICBmb250LnBvaW50U2l6ZTogMTAKICAgIEFib3V0SXRlbSB7 CiAgICAgICAgYW5jaG9ycy5maWxsOiBwYXJlbnQKICAgICAgICAKICAgICAgICBhYm91dERhdGE6 ICh7CiAgICAgICAgICAgIGRpc3BsYXlOYW1lOiAiU2hvcnQiLAogICAgICAgICAgICBwcm9kdWN0 TmFtZTogIlNob3J0IiwKICAgICAgICAgICAgY29tcG9uZW50TmFtZTogIlNob3J0IiwKICAgICAg ICAgICAgc2hvcnREZXNjcmlwdGlvbjogIlNob3J0IiwKICAgICAgICAgICAgaG9tZXBhZ2U6ICJo dHRwOi8vd3d3LmF1cmx0aGF0aXN0aGVsb25nZXN0dGhpbmdpbnRoZWZvcm0uY29tIiwKICAgICAg ICAgICAgYnVnQWRkcmVzczogIiIsCiAgICAgICAgICAgIHZlcnNpb246ICIxLjAiLAogICAgICAg ICAgICBvdGhlclRleHQ6ICIiLAogICAgICAgICAgICBhdXRob3JzOiBbXSwKICAgICAgICAgICAg Y3JlZGl0czogW10sCiAgICAgICAgICAgIHRyYW5zbGF0b3JzOiBbXSwKICAgICAgICAgICAgbGlj ZW5zZXM6IFsKICAgICAgICAgICAgICAgIHsKICAgICAgICAgICAgICAgICAgICBuYW1lOiAiIiwK ICAgICAgICAgICAgICAgICAgICB0ZXh0OiAiIiwKICAgICAgICAgICAgICAgICAgICBzcGR4OiAi IgogICAgICAgICAgICAgICAgfQogICAgICAgICAgICBdLAogICAgICAgICAgICBjb3B5cmlnaHRT dGF0ZW1lbnQ6ICLCqTIwMjIiLAogICAgICAgICAgICBkZXNrdG9wRmlsZU5hbWU6ICIiCiAgICAg ICAgfSkKICAgIH0KfQo= 151226 2022-08-10 15:00:13 +0000 2022-08-10 21:33:25 +0000 formlayout-freeze formlayout-freeze.qml text/x-qml 512 kbugs aW1wb3J0IFF0UXVpY2sgMi4xCmltcG9ydCBvcmcua2RlLmtpcmlnYW1pIDIuMTkKaW1wb3J0IFF0 UXVpY2suTGF5b3V0cyAxLjMKaW1wb3J0IFF0UXVpY2suQ29udHJvbHMgMi4xNSBhcyBRUUMyCgpR UUMyLkFwcGxpY2F0aW9uV2luZG93IHsKICAgIGZvbnQuZmFtaWx5OiAiVWJ1bnR1IgogICAgZm9u dC5wb2ludFNpemU6IDEwCiAgICAKICAgIC8vIG11c3QgYmUgbGFyZ2UgZW5vdWdoIHRvIGZpdCB0 aGUgZW50aXJlIHRleHQKICAgIHdpZHRoOiA0MDAKICAgIGhlaWdodDogNDAwCiAgICAKICAgIEZv cm1MYXlvdXQgewogICAgICAgIGFuY2hvcnMuZmlsbDogcGFyZW50CiAgICAgICAgCiAgICAgICAg VXJsQnV0dG9uIHsKICAgICAgICAgICAgdXJsOiAiaHR0cDovL3d3dy5hdXJsdGhhdGlzdGhlbG9u Z2VzdHRoaW5naW50aGVmb3JtLmNvbSIKICAgICAgICAgICAgd3JhcE1vZGU6IFRleHQuV29yZFdy YXAKICAgICAgICAgICAgTGF5b3V0LmZpbGxXaWR0aDogdHJ1ZQogICAgICAgIH0KICAgIH0KfQo= 151234 2022-08-10 21:33:25 +0000 2022-08-10 21:33:25 +0000 formlayout-freeze-notosans formlayout-freeze-notosans.qml text/x-qml 492 kbugs aW1wb3J0IFF0UXVpY2sgMi4xCmltcG9ydCBvcmcua2RlLmtpcmlnYW1pIDIuMTkKaW1wb3J0IFF0 UXVpY2suTGF5b3V0cyAxLjMKaW1wb3J0IFF0UXVpY2suQ29udHJvbHMgMi4xNSBhcyBRUUMyCgpR UUMyLkFwcGxpY2F0aW9uV2luZG93IHsKICAgIGZvbnQuZmFtaWx5OiAiTm90byBTYW5zIgogICAg Zm9udC5wb2ludFNpemU6IDkKICAgIAogICAgLy8gbXVzdCBiZSBsYXJnZSBlbm91Z2ggdG8gZml0 IHRoZSBlbnRpcmUgdGV4dAogICAgd2lkdGg6IDYwMAogICAgaGVpZ2h0OiA0MDAKICAgIAogICAg Rm9ybUxheW91dCB7CiAgICAgICAgYW5jaG9ycy5maWxsOiBwYXJlbnQKICAgICAgICAKICAgICAg ICBVcmxCdXR0b24gewogICAgICAgICAgICB1cmw6ICJodHRwOi8vd3d3LnVNQnFQaEZZdWxvMS5j b20iCiAgICAgICAgICAgIHdyYXBNb2RlOiBUZXh0LldvcmRXcmFwCiAgICAgICAgICAgIExheW91 dC5maWxsV2lkdGg6IHRydWUKICAgICAgICB9CiAgICB9Cn0K