245479 2022-09-21 08:12:41 -0700 REGRESSION (iOS 16): LocalStorage is cleared after quota error 2023-02-21 05:33:17 -0800 1 1 1 Unclassified WebKit Website Storage WebKit Nightly Build Unspecified iOS 16 RESOLVED FIXED InRadar P2 Major --- 1 alexey.buki sihui_liu akif.abasov nham sihui_liu webkit-bug-importer oldest_to_newest 1900139 0 462504 alexey.buki 2022-09-21 08:12:41 -0700 Created attachment 462504 test script that is shown the problem IOS16 Safari: LocalStorage is cleared after writing data of more than ~2.5MB. After upgrading on IOS 16 we were faced the problem clearing data in localStorage.When we try to write data that size is more than ~2.5MB or all amount of data more than ~2.5MB the LocalStorage is being cleared without any errors and warnings in Safari. I could not reproduce the problem in other browsers or platforms. Step to reproduce: - Go to IOS 16 Safari - Open any website - try to write data more than ~2.5MB (the attached test script helps you to display the problem) - check your localStorage Actial result: your localStorage is empty Expected result: your localStorage should be filled your data or it should be thrown an exception if quota is exceeded Please consider the problem ASAP. Thank you in advance! 1900283 1 webkit-bug-importer 2022-09-21 19:25:43 -0700 <rdar://problem/100252023> 1901565 2 sihui_liu 2022-09-27 10:43:55 -0700 Pull request: https://github.com/WebKit/WebKit/pull/4758 1902444 3 ews-feeder 2022-09-30 13:37:11 -0700 Committed 255044@main (0297f1253a4f): <https://commits.webkit.org/255044@main> Reviewed commits have been landed. Closing PR #4758 and removing active labels. 1902757 4 alexey.buki 2022-10-03 00:45:03 -0700 Can you share the IOS version where the issue will be fixed? thank you in advance! 1911938 5 nham 2022-11-11 17:25:02 -0800 I don't think this test script is correct. It measures the string length of all values in LocalStorage. But LocalStorage is persisted, and it's the size of the persisted string that matters for quota computations. Currently in WebKit, LocalStorage string values are persisted as UTF-16 (2 bytes per character)--see the call to SQLiteStatement::bindBlob(StringView) in SQLiteStorageArea::setItem. So I would expect that you could only store 2.5 million characters before exceeding your quota on disk. 1911961 6 nham 2022-11-11 21:15:57 -0800 Note that Chrome implements LocalStorage in the exact same manner: string values are persisted as UTF-16, so they use 2 bytes per character. However, their quota for LocalStorage is 10 MB (https://chromiumcodereview.appspot.com/21680002), so when you run your test case, you can store 5 million characters. We could possibly address this by discussing whether it's a good idea to bump up our quota as well. However, given the current 5 MB quota, the fact that you can only store 2.5 million characters in your test case is intended and things are working as expected. 1912351 7 sihui_liu 2022-11-14 09:46:44 -0800 Reopened as 255044@main is reverted in https://bugs.webkit.org/show_bug.cgi?id=247767. As Ben mentioned, WebKit stores string in LocalStorage as UTF-16, so it is expected that 5MB quota only allows about 2.5 million characters. The was implemented way before iOS 16, so likely not a regression. However, this could still be a compatibility issue as Safari has different behavior than Chrome and Firefox, so we should keep this bug and figure out how to solve it. 1912583 8 alexey.buki 2022-11-15 05:46:38 -0800 This issue is a regression because localStorage is cleared when the amount of storage is reached more than 2.5 million characters. It could not be reproduced before ios16. 1912658 9 sihui_liu 2022-11-15 10:18:50 -0800 (In reply to Olexiy from comment #8) > This issue is a regression because localStorage is cleared when the amount > of storage is reached more than 2.5 million characters. It could not be > reproduced before ios16. Oh so the regression is "LocalStorage is cleared after quota error", not "LocalStorage throws quota error after writing 2.5 million characters". Updated title to reflect that. 1913241 10 sihui_liu 2022-11-17 11:17:44 -0800 Pull request: https://github.com/WebKit/WebKit/pull/6597 1913601 11 ews-feeder 2022-11-18 17:23:57 -0800 Committed 256863@main (5bc131992783): <https://commits.webkit.org/256863@main> Reviewed commits have been landed. Closing PR #6597 and removing active labels. 1935483 12 akif.abasov 2023-02-21 05:33:17 -0800 It's even more broken in Safari Tech Preview https://bugs.webkit.org/show_bug.cgi?id=252661 462504 2022-09-21 08:12:41 -0700 2022-09-21 08:12:41 -0700 test script that is shown the problem defineMaxSizeLs.js text/javascript 832 alexey.buki ZnVuY3Rpb24gZGVmaW5lTWF4U2l6ZUxzICgpIHsKICAgIGNvbnN0IGl0ZW1TaXplID0gMTAyNCAq IDEwOwogICAgbGV0IG1heFNpemUgPSAwOwogICAgbGV0IGkgPSAwOwogICAgbGV0IGJ1ZmZlciA9 ICcnOwoKICAgIGZvciAobGV0IGsgPSAwOyBrIDwgaXRlbVNpemU7IGsrKykgewogICAgICAgIGJ1 ZmZlciArPSAnMCc7CiAgICB9CgogICAgY29uc3QgZ2V0U3RvcmFnZVNpemUgPSAoKSA9PiB7CiAg ICAgICAgdmFyIG9jY3VwaWVkID0gMDsKCiAgICAgICAgZm9yIChsZXQgaiA9IDA7IGogPCBsb2Nh bFN0b3JhZ2UubGVuZ3RoOyBqKyspIHsKICAgICAgICAgICAgb2NjdXBpZWQgKz0gbG9jYWxTdG9y YWdlW2xvY2FsU3RvcmFnZS5rZXkoaildLmxlbmd0aDsKICAgICAgICB9CgogICAgICAgIHJldHVy biBvY2N1cGllZDsKICAgIH07CgogICAgY29uc3QgcnVuID0gKCkgPT4gewogICAgICAgIGNvbnNv bGUubG9nKCdleHBlY3RlZCBzaXplID0gJywgbWF4U2l6ZSwgJ2FjdHVhbCBzaXplID0gJywgZ2V0 U3RvcmFnZVNpemUoKSk7CgogICAgICAgIHRyeSB7CiAgICAgICAgICAgIGxvY2FsU3RvcmFnZS5z ZXRJdGVtKCdfX190ZXN0JyArIGksIGJ1ZmZlcik7CgogICAgICAgICAgICBzZXRUaW1lb3V0KCgp ID0+IHsKICAgICAgICAgICAgICAgIG1heFNpemUgKz0gaXRlbVNpemU7CiAgICAgICAgICAgICAg ICArK2k7CiAgICAgICAgICAgICAgICBydW4oKTsKICAgICAgICAgICAgfSwgMTAwKTsKICAgICAg ICB9IGNhdGNoKGUpIHsKICAgICAgICAgICAgY29uc29sZS5sb2coJ21heCBzaXplJywgbWF4U2l6 ZSk7CiAgICAgICAgfQogICAgfTsKCiAgICBydW4oKTsKfQ==