How can i find the source of this font-related coretext warning in IOS13?

Solution 1:

There is another output in console, you can try to add a symbolic breakpoint

CoreText note: Set a breakpoint on CTFontLogSystemFontNameRequest to debug.

Solution 2:

I started experiencing this warning in the console starting with Xcode 11, with both MacOS and iOS targets.

You will receive ".SFUI-Regular" from UIFont.systemFont(ofSize: X).fontName. The warning will then occur if you try to instantiate using UIFont(name: fontName, size: size).

In my case I am letting the user customize the display font, but the default was ".SFUI-Regular", so I have changed that to "TimesNewRomanPSMT"

let defaultFont = UIFont.systemFont(ofSize: X).fontName

// replace with
let defaultFont = "TimesNewRomanPSMT"

UIFont(name: defaultFont, size: size)