Ignore ErrHelp with Parse when ExitOnError

[xjasonlyu]

Currently when we use -h or --help flag to print help message, it would add additional pflag: help requested to the end of message; or when some other errors occurred, it would print the error message twice (front and end).

It was caused by those codes,

pflag/flag.go

Lines 1144 to 1150 in 2e9d26c

	case ContinueOnError:
	return err
	case ExitOnError:
	fmt.Println(err)
	os.Exit(2)
	case PanicOnError:
	panic(err)

And in go's official flag package, it would explicitly ignore the ErrHelp error.

switch f.errorHandling {
case ContinueOnError:
	return err
case ExitOnError:
	if err == ErrHelp {
		os.Exit(0)
	}
	os.Exit(2)
case PanicOnError:
	panic(err)
}

I don't know if this was some kind of bug, but a little fixes might be better.🤗

[cornfeedhobo]

@xjasonlyu There is a PR for this somewhere, but this repo is completely neglected. This has been fixed on my fork, which has instructions for how to get working with cobra.

[xjasonlyu]

@cornfeedhobo Thanks.👍

[tmc]

@xjasonlyu please reopen this issue.

[JeffFaer]

@tomasaschan any chance we could get #407 merged to fix this issue?

It's easy enough to work around, but it feels kind of bad if every client of this library needs to do the same workaround...

[tomasaschan]

@JeffFaer Done - thanks for bringing this to my attention. It'll be in 1.0.8, when that's eventually released.