QA reports that the app sometimes freezes completely with no crash log. If you suspect a deadlock, in what order would you track down the cause?
Attach the debugger while it's frozen, look at every thread's backtrace, and find the locks and queues waiting on each other. If it's hard to reproduce, collect stacks from the moment of the hang with watchdog reports or MetricKit hang diagnostics.
ConcurrencyMultiple choiceBasics
You run this GCD code inside viewDidLoad of a UIKit view controller (main thread). What…
#deadlock #sync
ConcurrencyMultiple choiceAdvanced
You run this GCD code on the main thread. What's the output? …
#deadlock #sync
Performance and debuggingShort answerIntro
Once you've reproduced a bug, which Xcode debugging features do you actually reach for…
#debugging #lldb
Performance and debuggingMultiple choiceAdvanced
After a certain action the app freezes completely (no input response). Which of these are…
#deadlock #debugging