227224 2021-06-21 10:52:16 -0700 Text disappears for multiple seconds when font requested but load interrupted 2021-06-28 10:53:14 -0700 1 1 1 Unclassified WebKit Text Safari 14 All All NEW https://bugs.webkit.org/show_bug.cgi?id=227143 InRadar P2 Trivial --- 1 ian webkit-unassigned mmaxfield webkit-bug-importer oldest_to_newest 1771344 0 ian 2021-06-21 10:52:16 -0700 In Safari/Mobile Safari 14 text stops rendering for a several seconds in an peculiar circumstance: • Nothing on the page initially needed a font specified in @font-face. • A style was changed such that that font is now needed, triggering the lazy load. • The font-face in question has font-display:auto. • The font download is ~interrupted~ after it's requested. In Chrome, Firefox, and earlier versions of Safari there is an observable but brief 'blink' (maybe ~250ms), but in Safari 14 the disappearance can be several seconds long Reproduction is here: http://ianbellomy.com/test/font-failure-test.html (Note that caching may eliminate the issue if the page is refreshed.) Admittedly the situation is pretty peculiar but it also seems like 'auto' should not lead to a behavior like this. FWIW, I ran into this after having done something bone-headed but it seems possible to inadvertently hit this in a large project, if, through some project change, a font is no longer needed on initial presentation, and additional network traffic is needed to properly display the site. In a PWA type situation for example a user might install the PWA but not hit an area that needs a font until they go to use the PWA while offline. I haven't tested for a 'failed' response though (opposed to an interruption). 1773134 1 webkit-bug-importer 2021-06-28 10:53:14 -0700 <rdar://problem/79871859>