Bug 237968

Created attachment 454850 [details] Zip of files in the referenced github repo When manually constructing an SVG via JavaScript that uses an external stylesheet via `<use>`, no matter if the sprite is already rendered on the page, or if it's been downloaded before, it is always fetched over the network. This can lead to an excessive number of requests on pages that use JS to construct and deconstruct tooltips, menus, etc. Replication: - Clone https://github.com/Cherry/svg-external-sprite-redownloaded (also attached as zip to this ticket) - Run any server to serve this directory (npx serve for example) - Open resulting site, and watch network requests as both a PNG and SVG element are constructed and deconstructed every second Expected Results: `sprite.svg` to be only downloaded once Actual Results: `sprite.svg` is downloaded every second The replication was done using Safari 15.4 (17613.1.17.1.6) on MacOS 12.3. I did not test with iOS, but it's possible that's also impacted. I'm not sure if this is expected behaviour, but I did find a previous bug reporting similar things in the past: - https://www.smashingmagazine.com/2016/05/safari-svg-sprite-bug/ - https://bugs.webkit.org/show_bug.cgi?id=156368