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Date: Tue, 30 May 2023 04:42:55 +0200
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To: PHP internals <internals@lists.php.net>
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Subject: Let ReflectionMethod keep track of original class
From: andreas@dqxtech.net (Andreas Hennings)

Hello list,
this proposal will be useful in combination with "Declaration-aware attributes"


Problem
========
Currently, ReflectionMethod is not aware of the original class, if the
method is declared in a parent class.
Methods that are called during a discovery algorithm that need to
process a method with its original class typically need two
parameters:

function processMethod(\ReflectionClass $class, \ReflectionMethod $method) {..}


Proposal
========
Let a ReflectionMethod object keep track of the original class.
Introduce a new method ReflectionMethod->getOriginalClass() to retrieve it.

class B {
  function f($x) {}
}
class C extends B {}

foreach ([
  // There are different ways to get a reflection method object, all
of them track the original class.
  new ReflectionMethod('C', 'f'),
  (new ReflectionClass('C'))->getMethod('f'),
  (new ReflectionMethod('C', 'f'))->getParameters()[0]->getDeclaringFunction(),
] as $rm) {
  // The following won't change:
  assert($rm->class === 'B');
  assert($rm->getDeclaringClass()->getName() === 'B');
  // New method:
  assert($rm->getOriginalClass()->getName() === 'C');


Alternatives
==========

At first I thought we might introduce a new class like
"VirtualReflectionMethod" which behaves as if the method was declared
on the child class. But this is awkward.

I think the ->getOriginalClass() is much simpler.


--- Andreas