errorhelper

README

errorhelper

Helpers for Go's error.

Documentation

Overview

Package errorhelper contains error-related helpers.

Index

• func CallerError(err error, params ...any) error
• func Must[R any](r R, err error) R
• func Must0(err error)
• func Must2[R1, R2 any](r1 R1, r2 R2, err error) (R1, R2)
• func PanicToError(panicArg any, err *error)
• func UnwrapErrors(err error) []error

Examples

• CallerError

Functions

func CallerError

func CallerError(err error, params ...any) error

CallerError prepends the provided error with caller function/method name and the provided parameters. If there are no parameters, colon is used. If 'err' is nil, nil is returned.

Example

errf1 := CallerError(error1)
fmt.Println(errf1.Error())
errf2 := CallerError(error1, " ")
fmt.Println(errf2.Error())
ermth := errMethod{}
errm1 := ermth.Error1()
fmt.Println(errm1.Error())
errm2 := ermth.Error2()
fmt.Println(errm2.Error())

Output:
ExampleCallerError:error1
ExampleCallerError error1
errMethod.Error1: error1
(*errMethod).Error2--error1

func Must

func Must[R any](r R, err error) R

Must returns 'r' if 'err' is nil. Otherwise, it panics with 'err'.

func Must0

func Must0(err error)

Must0 panics with 'err', if 'err' is not nil.

func Must2

func Must2[R1, R2 any](r1 R1, r2 R2, err error) (R1, R2)

Must2 returns ('r1', 'r2') if 'err' is nil. Otherwise, it panics with 'err'.

func PanicToError

func PanicToError(panicArg any, err *error)

PanicToError converts panic to error in the following way:

• if surrounding function panics with an error, this error is returned;
• if surrounding function panics with a string, the error wrapping this string is returned;
• if surrounding function panics with a fmt.Stringer, the error wrapping fmt.Stringer.String is returned;
• if surrounding function panics with an encoding.TextMarshaler, the error wrapping encoding.TextMarshaler.MarshalText is returned;
• otherwise the panic is reraised.

PanicToError must be called from a defer statement:

func Example() (err error) {
  defer func() {
    PanicToError(recover(), &err)
  }()
  return nil
}

(See tests.)

func UnwrapErrors

func UnwrapErrors(err error) []error

UnwrapErrors returns the result of calling Unwrap method on 'err', in case if err's type contains an Unwrap method that returns []error. Otherwise or if the Unwrap method returns single error, UnwrapErrors returns nil.