macOS Big Sur 11.0 crash on [paragraphStyle setParagraphStyle: [NSParagraphStyle defaultParagraphStyle]];

Number:rdar://FB8930278 Date Originated:6 dec 2020
Status:Open Resolved:
Product:macOS API Product Version:11.0, 11.0.1, 11.1,
Classification:Crash Apple API Reproducible:Yes
Immediate crash with exception when calling these lines (macOS 11.0.1 & macOS 11.1) :

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle setParagraphStyle:[NSParagraphStyle defaultParagraphStyle]];

It occurs on all Intel Apple computers.
It doesn’t affect M1 Apple computers.


macOS Preference: __NSDisableSharingTextTabInstance

After some more investigations, it seems related to a preference created by macOS (“__NSDisableSharingTextTabInstance”):

int main(int argc, const char *argv[]) {

[[NSUserDefaults standardUserDefaults] setBool: YES forKey: @"__NSDisableSharingTextTabInstance"]; // -> What is it? Created by old version of macOS ???

// Uncomment this line to make it works !
//[[NSUserDefaults standardUserDefaults] removeObjectForKey: @"__NSDisableSharingTextTabInstance"];

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];

// It crashes here, if __NSDisableSharingTextTabInstance was YES
[paragraphStyle setParagraphStyle:[NSParagraphStyle defaultParagraphStyle]];

return NSApplicationMain(argc, argv);


By rossetantoine at Dec. 12, 2020, 9 a.m. (reply...)

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