What is a panic in Go and how does it differ from an error? How to catch a panic?

In Go, panic is a mechanism used to handle critical errors, after which the program execution usually terminates. A panic causes the current goroutine to stop immediately and begins the process of stack unwinding, calling deferred functions (defer).

Differences from an error:

• Error (error) — is a regular value returned by a function and can be handled normally.
• Panic (panic) — is an emergency signal about a serious problem, usually not intended for normal handling.

To catch a panic and prevent the program from crashing, the recover() function is used, which can be called inside a deferred function (defer). If recover() is called during stack unwinding, it returns the panic value and stops its propagation.

Example:

func safeCall() {
    defer func() {
        if r := recover(); r != nil {
            fmt.Println("Caught a panic:", r)
        }
    }()

    panic("something went wrong")
}

func main() {
    safeCall()
    fmt.Println("The program continues")
}