go-joinederror

Small library for unpacking errors into a slice that were combined using the errors.Join() function in Go 1.20.

Install

$ go get github.com/mrflynn/go-joinederror

Usage

This library provides two ways to unpack joined errors. UnwrapMany unpacks the top level joined errors, and UnwrapAll recursively unpacks all joined errors at every level. For example,

// Create a joined error.
err := errors.Join(
	errors.New("lorem"),
	errors.New("ipsum"),
	errors.Join(errors.New("dolor"), errors.New("sit")),
)

// UnwrapMany:
comparison := []error{
	errors.New("lorem"),
	errors.New("ipsum"),
	errors.Join(errors.New("dolor"), errors.New("sit"))
}

fmt.Println(reflect.DeepEqual(joinederror.UnwrapMany(err), comparison)) // Prints true

// UnwrapAll:
comparison := []error{
	errors.New("lorem"),
	errors.New("ipsum"),
	errors.New("dolor"),
	errors.New("sit"),
}

fmt.Println(reflect.DeepEqual(joinederror.UnwrapAll(err), comparison)) // Prints true