How to debug and handle errors returned by functions in Go?

To debug and handle errors returned by functions in Go, you can follow these steps:

Check for errors: Most functions in Go return an error as their last return value. Begin by checking if an error occurred by comparing the returned error with nil using the if statement.

result, err := SomeFunction()
if err != nil {
    // handle error
}

Print error details: If an error occurs, print the details of the error for debugging purposes. You can use the fmt.Printf or log.Printf functions to display the error message along with additional information.

result, err := SomeFunction()
if err != nil {
    fmt.Printf("Error: %v\n", err)
    // handle error
}

Handle or report the error: Depending on the situation, you may want to handle the error or report it to another function or system. For example, you can log the error, return it to the caller, or try an alternative action.

result, err := SomeFunction()
if err != nil {
    // handle the error, e.g., return an error to the caller
    return err
}

Use error types for specific errors: Instead of comparing error messages, you can create custom error types to differentiate between specific errors. This enables you to handle each error type differently.

type MyError struct {
    message string
}

func (e *MyError) Error() string {
    return e.message
}

func SomeFunction() error {
    // code that can produce an error
    if someCondition {
        return &MyError{"Some error occurred"}
    }
    return nil
}

func main() {
    result, err := SomeFunction()
    if err != nil {
        if myErr, ok := err.(*MyError); ok {
            // handle specific error type
        } else {
            // handle general error
        }
    }
}

Recover from panics: In some situations, a function might panic instead of returning an error. To handle such exceptions, you can use the recover function inside a deferred function call. This allows the program to safely continue its execution even if a panic occurs.

func SomeFunction() {
    defer func() {
        if r := recover(); r != nil {
            fmt.Printf("Panic occurred: %v\n", r)
        }
    }()
    // code that can cause a panic
    panic("Something went wrong")
}

By following these steps, you can effectively debug and handle errors returned by functions in Go.