Most methods do not consider constants with same values.

[keithmifsud]

Thanks for this library MyClabs :)

Not sure if this should be resolved or not. I find it problematic that when searching, the method does not consider that there may be several constants with same values. Example of an international dialling code enum:

const ITA = '39'; // this is fine and unique value.
const IMN = '44'; // UK and Isle of Man share the same code.
const GBR = '44'; // UK and Isle of Man share the same code.

Then when I instantiate the Enum like so:

        $testEnum = new CountryCallingCode(CountryCallingCode::GBR);
        var_dump($testEnum->getKey()); // return IMN not GBR!!

[mnapoli]

:+1:, I think supporting multiple identical values in the same enum is problematic. I'm not sure we could enforce it strictly without loosing in performances though 🤔

[keithmifsud]

If it was to be done, how would you go about it? I'm asking so I can understand what you mean in performance loss.

[keithmifsud]

I encountered this issue in several domains including foreign exchange rates, foreign exchange currency codes and other more custom ones such as that a status can be different but the value the same. Example of "LeadStatus" enum:

const ACQUIRED = "Open"; const PENDING _QUALIFICATION= "Open"; const QUALIFIED = "Closed"; const NOT_QUALIFIED = "Closed";

[mnapoli]

Oh OK, maybe it's not so uncommon to have duplicate values… I did not think about it much.

I was thinking about ensuring that there are no duplicate values, but that's costly to do. I'm not sure there is much we can do here :/

[keithmifsud]

I understand. Enums can have same value even in C language :)

But again this is a matter of how one uses Enums. The LeadStatus enum example can be changed so that the values do meet their name but cases like I had with the country calling codes cannot be refactored.

I also tried using another library from MabeEnum and it also produces the same unexpected result. Therefore, for a demo https://github.com/keithmifsud/laravel-ddd-demo/blob/master/src/Domain/Member/PhoneNumber/InternationalDialingCode.php I ended up querying by the value which is obviously very bad practice because I'm not really getting an Enum Constant but simply matching the first constant of similar value.

I guess we'll have to develop a new Enum library or ditch Enms in PHP. I any case, I would at least disallow instantiating Enums by value since this will break the dev's code when there are identical values.

What do you think? I think that if an Enum is allowed to have different constants with same value then wither disallow this or disallowing instantiating/querying by value since it will return the first constant and not the actual one.

[danielbeardsley]

It seems quite odd to me to treat an Enum as a map. Generally, an enum is a human-readable and type-safe wrapper around some set of distinct values.

You situation seems better suited to using a map between two enums:

$map = [
  LeadStatus::AQUIRED => Status::OPEN,
  ...
]