issue_link

#104646

Commit Hash

b7eaad8

Target

stable

Impacted Users

Flutter Web app users on Safari 13

Impact Description

The flutter.js file utilizes JS syntax slightly newer than what Safari 13 is able to understand, so:

• Users on Safari 13 (both on iDevices and MacOSX)
• Visiting a Flutter Web app that uses the new initialization

Will see a blank screen (and a few errors in the console, see above).

The impact should be rather low. According to caniuse.com, Safari 13 on iOS accounts for 0.21% of all users globally, and Safari 13 for MacOS: 0.4%. Data.

Workaround

Since the flutter.js is statically generated, users may be able to start any new flutter project for web, generate the flutter.js file there, and bring it to their "broken" projects before uploading. It's cumbersome (flutter.js gets re-generated after every flutter clean) but doable.

Risk

low

Test Coverage

no

Validation Steps

Having an iOS Simulator running iOS 13.X, deploy any flutter web app with the new index.html (that uses flutter.js), and it should work. Currently it doesn't.

Sanity check:

• Gallery (broken): https://gallery.flutter.dev (the "F" from the loader never finishes loading, errors in the JS console)
• Example (fixed): https://dit-bootstrap-tests.web.app (the counter app starts normally, no errors on the JS console)