Error Propagation

Error propagation in Swift is the process of passing an error up the call stack until it's handled by a catch block. When a function encounters an error it can't resolve, it throws the error. The calling function then has the responsibility to either handle the error using a do-catch block or to propagate the error further up the chain by also declaring that it throws. This continues until the error is caught and handled, preventing the program from crashing and allowing for graceful error recovery.