Add additional methods for reflections that have attributes

[ollieread]

Description

All currently attributable reflections have a single method relating to attributes.

getAttributes(?string $name = null, int $flags = 0): array

Additional methods for dealing with attributes would be a nice improvement and would simplify common approaches. I'm proposing the following methods.

getAttribute

Get a single instance of ReflectionAttribute, following the same rules as getAttributes, minus the fact that $name is required.

getAttribute(string $name, int $flags = 0): ?ReflectionAttribute

If more than one attribute matches, an exception should be thrown.

hasAttribute

Functionally identical to getAttribute, except it will return true if one or more matches are found, otherwise it returns false.

hasAttribute(string $name, int $flags = 0): bool

getNumberOfAttributes

Again, follows the same rules as getAttributes, but will return the number found. This particular method is based on the ReflectionFunctionAbstract::getNumberOfParameters method.

getNumberOfAttributes(?string $name = null, int $flags = 0): int

[iluuu1994]

Getting a singular attribute of a specific class is most likely the default case, so I'm definitely in support of the first two. As for getNumberOfAttributes, I'm not completely sure it's necessary, as count($reflection->getAttributes()) would do the job for this less common case. But I don't have strong feeling about it.

I think I think this discussion might be better suited for the mailing list. I'm not sure this necessarily needs an RFC but a mention on the mailing list would certainly not hurt.

[ollieread]

Getting a singular attribute of a specific class is most likely the default case, so I'm definitely in support of the first two. As for getNumberOfAttributes, I'm not completely sure it's necessary, as count($reflection->getAttributes()) would do the job for this less common case. But I don't have strong feeling about it.

The idea behind this was that it follows ReflectionFunctionAbstract::getNumberOfParameters() and it functions as a hasAttribute for attributes where the number of them is important.

$methods = array_map(function (ReflectionMethod $method) {
    return $method->getNumberOfAttributes(MyAttribute::class) === 2;
}, $reflection->getMethods());

I think I think this discussion might be better suited for the mailing list. I'm not sure this necessarily needs an RFC but a mention on the mailing list would certainly not hurt.

I actually have a whole list of suggestions for various improvements to Reflection in general, one of which is #8488. Perhaps I should write them all up, in a gist or something, then float the idea on the mailing list? If people are interested, and if necessary, I can then make a PR and maybe even attempt some of them myself.

[ollieread]

@iluuu1994 I've written up a bunch of my thoughts about improvements to reflection in a gist. Here's the link to the attributes specific stuff: https://gist.github.com/ollieread/34c878bf120ee70f9d2a869cb7a242d1#attributes

I am happy to try and start a discussion on the mailing list, though I would request a point in the right direction, and how best to start it. I've not participated in any of the PHP mailing lists, and the last two weeks have been my first time contributing in any way to PHP, so I'm not sure how best to go about it.

[iluuu1994]

The suggestions seem mostly reasonable. I have a few comments:

• The name matches/accepts sound somewhat generic. Inspired from C#, something like is{Sub,Super}TypeOf and isAssignable{From,To} (I'm not sure if we need both directions)
• of might be better named as fromString
• I can't imagine a case where hasParameter would be useful. Do you have something in mind? hasParameter doesn't really provide adequate information to call an unknown function.

Participating on the mailing list is straight forward. https://www.php.net/mailing-lists.php Subscribe to the "internals" list and send an e-mail about your subject and ask for feedback.

[ollieread]

• I can't imagine a case where hasParameter would be useful. Do you have something in mind? hasParameter doesn't really provide adequate information to call an unknown function.

This was mostly an attempt to introduce consistency, whereby any elements that have child elements with unique names, are retrievable as a whole or individually and their presence can be checked.

Though I do see your point, it's probably not needed.

Participating on the mailing list is straight forward. https://www.php.net/mailing-lists.php Subscribe to the "internals" list and send an e-mail about your subject and ask for feedback.

Thanks, I'll update the gist and drop an email. Thank you for the help.

[ollieread]

I've sent the ideas to the mailing list @iluuu1994; I will await some responses, though I assume it's often a slow process. I'll also close this and my other feature request for now and open a new one that covers the gist when I get the chance to. Thanks for your help.

[ollieread]

I didn't hear much back from the mailing list @iluuu1994, though I didn't hear anyone against it.

I'd like to pick back up with the attribute-specific methods, getAttribute(), hasAttribute() and getNumberOfAttributes().

Furthermore, I'm relatively certain I've figured out how to achieve this. Should I go back to the mailing list for more feedback, or is it worth just opening a PR?