Can I recover from panic, handle the error, then panic again and keep the original stack trace?

Question

Is it possible to "rethrow" an error from recover and keep the original stack trace? The best I know how to do is to panic again, but that does create a new stacktrace.

func do() {
    defer func() {
        cleanUp()
        if x := recover(); x != nil {
            handleError()
            panic(x)
        }
    }()
    doStuff()
}

My motivation for wanting this is that unless my function exits normally or handleError runs, my program deadlocks. And unless I preserve the original strack trace, I do not know where it crashed.

Answer 1

The solution is to not call recover, because then neither rethrowing nor accessing the stack trace is possible. Use a bool flag instead of recover to check for panic.

https://play.golang.org/p/PKeP9s-3tF

func do() {
    panicked := true
    defer func() {
        cleanUp()
        if panicked {
            handleError()
        }
    }()
    doStuff()
    panicked = false
}

Answer 2

Defered functions higher up in the stack will run on panic, even if they don't call recover().

Simply remove the if-statement and the re-panic. Then handle your error, and let the panic continue up the stack.

func do() {
    defer handleError()
    doStuff()
}

a simple demo:

https://play.golang.org/p/UiRou5MhUR

func a() {
    defer func() {
        fmt.Println("a")
    }()
    panic("test")
}
func b() {
    defer func() {
        fmt.Println("b")
    }()
}

func main() {
    fmt.Println("Hello, playground")
    b()
}

outputs

Hello, playground
b