I am trying to track down the source of a strange crash that is happening for a client. It is happening in a multiwindow application built with Xojo 2018 R2 (It can not be build with newer versions do to some dependency issues) running on OSX 10.14.3.
The problem does not seem seem to occur in a regular fashion, but it always coincides with a window being closed, however it is not always the same window or even same type of window. I added logging to the close events of windows to track execution, but the take down all completes and the close event ends without incidence. Then the app crashes. I have had the client send me the system crash reports and I see:
Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000020 Exception Note: EXC_CORPSE_NOTIFY Termination Signal: Segmentation fault: 11 Termination Reason: Namespace SIGNAL, Code 0xb Terminating Process: exc handler  Application Specific Information: objc_msgSend() selector name: release
as well as
Exception Type: EXC_BAD_INSTRUCTION (SIGILL) Exception Codes: 0x0000000000000001, 0x0000000000000000 Exception Note: EXC_CORPSE_NOTIFY Termination Signal: Illegal instruction: 4 Termination Reason: Namespace SIGNAL, Code 0x4 Terminating Process: exc handler  Application Specific Information: *** CFRelease() called with NULL ***
Based on those reports, its not a leak, looks more like a bad reference somewhere. I have checked to see if there is some background process or asynchronous type of call that is happening that would not be caught by Xojo's UnhandledException event, but there is none.
Any ideas on how to further try to track this down?