Different NSFileHandler behavior in "Run" and "Test" modes

Question

Xcode : 15.0.1 (15A507) Mac OS: 14.3.1

I am working on Mac OS application which should parse files in binary format. This is document based application, but before I'll prepare visual representation, I want to parse file and create some kind of internal representation.

I got stuck with debugging code:

    @try {
        NSFileHandle *fileHandle;
        
        NSFileManager *fm = [NSFileManager defaultManager];
        if ([fm fileExistsAtPath:self.filePath]) {
            // Yes! File exists - shown both in "Run" and "Test" mode
            fileHandle = [NSFileHandle fileHandleForReadingAtPath:self.filePath];
            // return nil in "Run" mode
            if (fileHandle) {
                [fileHandle seekToFileOffset:0];    // перемотка в начало для уверенности
                self.header = [[EDFHeader alloc] initWithFile:fileHandle];
                
                if (self.header) {
                   // Load data...
                }
            }
            else {
                // Cannot open file! Get hererin "Run" mode 
               [NSException raise:INVALID_FILE_ACCESS  format:FILE_NOT_OPEN];
            }
         }
        
    }
    @catch (NSException *exception) {
            @throw;
    }

In Run mode (Cmd-R) I gor exception, as fileHandle returned is nil. As soon I am trying to run it through testing mode (Cmd-U) file is accessed and I can work without any problems.

I suspect that Run and Test modes have different assumptions about "sandboxing". But, unfortunately, I do not see any mention about sandbox in in latest Xcode.

I switch on access to User selected files in application' profile but no changes.

will be grateful for any ideas.

Thanks in advance.

• Tried to run code in Test mode and in Run mode in the Xcode. Works OK in Test mode, and cannot open file in Run mode.

• I tried to "downgrade" to use minimal Unix-like construction:

   FILE *libFile = fopen("/Users/<MyUserDir>/AI/EDF Analysezer/TestFiles/6720119.edf","r");
    if(libFile){
    char wah[200];
    fgets(wah, 200, libFile);
    printf("%s test\n", wah);
        }

Behavior is the same :-(

So I suggest issue is in some environment or application setting, not in the code itself.