Please help resolve Crash in guard let statement

Question

Created Aug ’22

Replies 2

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Participants 3

I have a swift code that accesses an obj-C class's string property. Like this: guard let unwrappedStr = objC.str

Crash stems in the above unwrapping line. Getting -[NSNull _fastCStringContents:]: unrecognized selector sent to instance I am unable to reproduce it on my device while debugging.

CoreFoundation__exceptionPreprocess (CoreFoundation)

libobjc.A.dylib	objc_exception_throw (libobjc.A.dylib)
CoreFoundation	+[NSObject(NSObject) _copyDescription] (CoreFoundation)
CoreFoundation	forwarding (CoreFoundation)
CoreFoundation	_CF_forwarding_prep_0 (CoreFoundation)
libswift...re.dylib	specialized withCocoaASCIIPointer(:requireStableAddress:work:) (libswiftCore.dylib)
libswift...re.dylib	bridgeCocoaString(:) (libswiftCore.dylib)
libswift...re.dylib	String.init(_cocoaString:) (libswiftCore.dylib)
libswift...on.dylib	static String.unconditionallyBridgeFromObjectiveC(:) (libswiftFoundation.dylib)

The issue as far as I investigated pops up in the objC to swift bridging calls so any help is appreciated.

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Answer 1

Claude31 OP

Aug ’22

Please show code:

objC class
more code where the error occurs

could you add a print before guard

print("str", objC.str)

0

Answer 2

DTS Engineer OP

Apple

Aug ’22

I am not able to reproduce it in my build

Please post a full crash report, per the instructions in Posting a Crash Report.

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