errors_go_other.go

//go:build !go1.20
// +build !go1.20

package jwt

import (
"errors"
"fmt"
)

// Is implements checking for multiple errors using [errors.Is], since multiple
// error unwrapping is not possible in versions less than Go 1.20.
func (jejoinedError) Is(errerror) bool {
for_, e:=rangeje.errs {
iferrors.Is(e, err) {
returntrue
 }
 }

returnfalse
}

// wrappedErrors is a workaround for wrapping multiple errors in environments
// where Go 1.20 is not available. It basically uses the already implemented
// functionality of joinedError to handle multiple errors with supplies a
// custom error message that is identical to the one we produce in Go 1.20 using
// multiple %w directives.
typewrappedErrorsstruct {
msgstring
joinedError
}

// Error returns the stored error string
func (wewrappedErrors) Error() string {
returnwe.msg
}

// newError creates a new error message with a detailed error message. The
// message will be prefixed with the contents of the supplied error type.
// Additionally, more errors, that provide more context can be supplied which
// will be appended to the message. Since we cannot use of Go 1.20's possibility
// to include more than one %w formatting directive in [fmt.Errorf], we have to
// emulate that.
//
// For example,
//
// newError("no keyfunc was provided", ErrTokenUnverifiable)
//
// will produce the error string
//
// "token is unverifiable: no keyfunc was provided"
funcnewError(messagestring, errerror, more...error) error {
// We cannot wrap multiple errors here with %w, so we have to be a little
// bit creative. Basically, we are using %s instead of %w to produce the
// same error message and then throw the result into a custom error struct.
varformatstring
varargs []any
ifmessage!="" {
format="%s: %s"
args= []any{err, message}
 } else {
format="%s"
args= []any{err}
 }
errs:= []error{err}

for_, e:=rangemore {
format+=": %s"
args=append(args, e)
errs=append(errs, e)
 }

err=&wrappedErrors{
msg: fmt.Sprintf(format, args...),
joinedError: joinedError{errs: errs},
 }
returnerr
}