iOS 15 crash with objc_getClass

Question

Created Jan ’24

Replies 3

Boosts 0

Participants 2

Hello. iOS 15 and its version of Swift had an issue with applying class level annotations, such as @available to the members of its class. When we attempt to use our Objective-C library to get the class, if there are things inside the class not available on iOS 15, then the call to objc_getClass crashes with EXC_BAD_ACCESS. This appears to have been fixed on iOS 16 and newer, however, as we still support iOS 15, is there a better workaround than having to annotate every needed member of the class with @available, instead of being able to use the class level annotation?

Boost

Answer 1

DTS Engineer OP

Apple

Jan ’24

I’ll need more details to offer any advice here. Let’s start with the basics: Please post an Apple crash report of the problem, per the advice in Posting a Crash Report.

Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"

0

Answer 2

stevem-newr OP

Jan ’24

The text version of the crash report should be attached. There are two relevant snippets of code for this crash to happen:

@available(iOS 16.0, *)
@MainActor
final class ScanViewModel {

    var scanTextType: DataScannerViewController.TextContentType?

    @Published var recognizedItems: [RecognizedItem] = []
}

In this block, we use the @available annotation to try and stop things that don't exist in iOS 15 from being accessed. Later, in instrumentation:

    unsigned int classNameCount = 0;
    const char **classNames = objc_copyClassNamesForImage(mainImageName, &classNameCount);
    for (NSUInteger i = 0; i < classNameCount; i++) {
        Class cls = objc_getClass(classNames[i]);
        NRMA__processClass(cls, results, parents);
    }
    free(classNames);

This crashes on the call to objc_getClass() when passed the class which has the @available annotation.

What I am asking is if there is a workaround for this bug in iOS 15 (this doesn't happen on iOS 16 and above)? Thank you.

Crash15-2024-01-16-093511.txt

0

Answer 3

stevem-newr OP

Jan ’24

Hi. Is there a more convenient workaround, or something that can perhaps be done when calling objc_getClass to avoid this crash, or am I doomed to have to annotate every aspect of the class until iOS 15 goes out of style?

0