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 PackageCallerError(err error, params ...any) error
• func PanicToError(panicArg any, err *error)
• func UnwrapErrors(err error) []error

Examples

• CallerError
• PackageCallerError

Functions

func CallerError

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

CallerError prepends the provided error error's 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.Error11()
fmt.Println(errm1.Error())
errm2 := ermth.Error12()
fmt.Println(errm2.Error())

Output:

ExampleCallerError:error1
ExampleCallerError error1
errMethod.Error11: error1
(*errMethod).Error12--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 PackageCallerError

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

PackageCallerError prepends the provided error's Error() with caller function/method name prepended with package name and the provided parameters. If there are no parameters, colon is used. If 'err' is nil, nil is returned.

Example

errf1 := PackageCallerError(error1)
fmt.Println(errf1.Error())
errf2 := PackageCallerError(error1, " ")
fmt.Println(errf2.Error())
ermth := errMethod{}
errm1 := ermth.Error21()
fmt.Println(errm1.Error())
errm2 := ermth.Error22()
fmt.Println(errm2.Error())

Output:

errorhelper.ExamplePackageCallerError:error1
errorhelper.ExamplePackageCallerError error1
errorhelper.errMethod.Error21: error1
errorhelper.(*errMethod).Error22--error1

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.