adds check for receiver names length

[chavacava]

Closes #1040
The rule receiver-naming now accepts an optional argument indicating the maximum length of receiver names. If no argument is provided the rule does not check for names length.

[ccoVeille]

That's a function wide if statement

I would suggest this instead

Suggested change

	func (r *ReceiverNamingRule) configure(arguments lint.Arguments) {
	r.Lock()
	defer r.Unlock()
	if r.receiverNameMaxLength == 0 {
	if len(arguments) < 1 {
	r.receiverNameMaxLength = defaultReceiverNameMaxLength
	return
	}
	arg := arguments[0]
	argStr, ok := arg.(string)
	if !ok {
	panic(fmt.Sprintf("Invalid argument for %s rule. Expecting an string, got %T", r.Name(), arg))
	}
	parts := strings.Split(argStr, "=")
	if len(parts) != 2 {
	panic(fmt.Sprintf("Invalid argument for %s rule. Expecting an string of the form 'key=value', got %s", r.Name(), argStr))
	}
	key := strings.TrimSpace(parts[0])
	value := strings.TrimSpace(parts[1])
	switch key {
	case "max-length":
	var err error
	r.receiverNameMaxLength, err = strconv.Atoi(value)
	if err != nil {
	panic(fmt.Sprintf("Invalid value %s for the configuration key max-length, expected integer value: %v", value, err))
	}
	default:
	panic(fmt.Sprintf("Unknown configuration key %s for %s rule.", key, r.Name()))
	}
	}
	}
	func (r *ReceiverNamingRule) configure(arguments lint.Arguments) {
	r.Lock()
	defer r.Unlock()
	if r.receiverNameMaxLength > 0 {
	return
	}
	if len(arguments) < 1 {
	r.receiverNameMaxLength = defaultReceiverNameMaxLength
	return
	}
	arg := arguments[0]
	argStr, ok := arg.(string)
	if !ok {
	panic(fmt.Sprintf("Invalid argument for %s rule. Expecting a string, got %T", r.Name(), arg))
	}
	parts := strings.Split(argStr, "=")
	if len(parts) != 2 {
	panic(fmt.Sprintf("Invalid argument for %s rule. Expecting a string of the form 'key=value', got %s", r.Name(), argStr))
	}
	key := strings.TrimSpace(parts[0])
	value := strings.TrimSpace(parts[1])
	switch key {
	case "max-length":
	var err error
	r.receiverNameMaxLength, err = strconv.Atoi(value)
	if err != nil {
	panic(fmt.Sprintf("Invalid value %s for the configuration key max-length, expected integer value: %v", value, err))
	}
	default:
	panic(fmt.Sprintf("Unknown configuration key %s for %s rule.", key, r.Name()))
	}
	}

Also I fixed the typo an string twice

[denisvmedia]

Why did you decide to have this way of configuration? This seems to be different comparing to what we have in the other rules. We either have ints directly or we have named args as in unchecked-type-assertion.

[denisvmedia]

LGTM