[BUG FIX] fix bug where user cannot set expiration date with memcached-cli

[zilllaiss]

simple fix since it only caused by wrong usage of operator and off-by-1 error.

[yeqown]

Please update here condition too, we assume the expiration is at the fourth postional argument, so there's not neccessary len(args) strictly equal to 4

[zilllaiss]

by looking at the other example (e.g. handleIncr()), I'm assuming you meant something like this?

	if len(args) != 3 && len(args) != 4 {
		return fmt.Errorf("usage: set <key> <value> [expiration]")
	}

	var expiration time.Duration
	if len(args) == 4 {
		if e, err := strconv.ParseUint(args[3], 10, 32); err == nil {
			expiration = time.Duration(e) * time.Second
		}
	}

instead of removing the length check like this...

	if len(args) != 3 {
		return fmt.Errorf("usage: set <key> <value> [expiration]")
	}

	var expiration time.Duration
	if e, err := strconv.ParseUint(args[3], 10, 32); err == nil {
		expiration = time.Duration(e) * time.Second
	}

...since the latter will ignore extra arguments i.e. when len(args) > 4. Is that correct?

[yeqown]

len(args) == 4 to be len(args) >= 4·
keep it's safe to access the expiration index, and work expected event args has more than 4 args

[yeqown]

Thanks for your contribution 🎉