A Mac Catalyst App Creates an AppKit Bundle Plugin in which @available does not work。
In AppKit Bundle Plugin, there is not watchOS and iOS version can not be higher than 28, but the log has been output. if (@available(watchOS 18.0, *)) { NSLog(@"bundle is available watchOS"); }
if (@available(iOS 28.0, *)) { NSLog(@"bundle is available iOS"); }
demo link: https://pan.baidu.com/s/1s_5qmsL6Bh-df3A1PfD0OA Extracted code: 5ndj
Placing a macOS bundle target inside of a Mac Catalyst app in order to use AppKit is not a supported configuration. See the Important box in the documentation);
Mac apps built with Mac Catalyst can only use AppKit APIs marked as available in Mac Catalyst, such as NSToolbar and NSTouchBar. Mac Catalyst doesn’t support accessing unavailable AppKit APIs.
Since there's no supported scenario for your target setup as you show, we cannot reason about the circumstances pertaining to the availability checking here.
Please file enhancement requests for any functionality from AppKit that you would like to see available in the Mac Catalyst environment.
— Ed Ford, DTS Engineer