Bug #71119 [Nab]: Cannot override methods on extended classes
Edit report at https://bugs.php.net/bug.php?id=71119&edit=1
ID: 71119
User updated by: chazmead89 at gmail dot com
Reported by: chazmead89 at gmail dot com
Summary: Cannot override methods on extended classes
Status: Not a bug
Type: Bug
Package: *General Issues
Operating System: Mac OSX 10.8.5
PHP Version: 7.0.0
Block user comment: N
Private report: N
New Comment:
So here's my usecass.. I have a class, which is invokable, I use a dependancy injector to call
the invoke method, the class defines a bunch of other methods which invoke uses to create a
callable.
simplified:
class A {
protected $_class = NULL;
protected $_method = NULL;
public function __construct(string $class, string $method) {
$this->_class = $class;
$this->_method = $method;
}
public function __invoke(Dependancy $dep) {
$c = $this->getCallable();
return $c($dep);
}
protected function getCallable(): callable {
return [ new $this->_class, $this->_method ];
}
}
Now I want to add extra dependancies to an extending class for additional functionality:
class B extends A {
public function __invoke(Dependancy $dep, Additional $dep2) {
// DO some additional stuff...
if ( $dep2 === True ) {
$c = [ $this, 'anotherCallableBecauseTrue' ];
return $c($dep, $dep2);
}
return parent::__invoke($dep);
}
}
This was never an issue in PHP5.. so I guess can you link me to the RFC discussion where this was
changed?
Previous Comments:
------------------------------------------------------------------------
[2015-12-15 14:08:30] nospam at example dot org
"someone with brain" is 100% of php team and all of them will agree that 1- all
dynamically typed languages don't have method overloading 2- it's pretty much impossible
for them to have it 3- you should use java
------------------------------------------------------------------------
[2015-12-15 14:04:29] inefedor at gmail dot com
I'm not sure why you're putting a slash between overriding and overloading, these two are
completely different matters.
Overloading is a form of dynamic dispatch when the concrete method is found during runtime based on
the instance type AND argument types. PHP doesn't have that meaning that.
Now overriding is when you override a method with another polymorphic method. They have to be
compatible, otherwise due to the nature of PHP's method dispatch (when all methods are virtual)
you'd have an error in otherwise type-safe cases like this:
class A { function foo(A $a) {} }
class B { function foo(B $a) {} }
$a = new B;
bar($a);
function bar(A $a) {
$a->foo(new A);
}
------------------------------------------------------------------------
[2015-12-15 14:00:42] nikic@php.net
FYI "override" and "overload" are not the same thing. What you say would make
sense if this would create a method overload. However PHP does not support method overloading.
------------------------------------------------------------------------
[2015-12-15 09:00:41] chazmead89 at gmail dot com
What about this test case then, called Method overloading..
class A {
public function foo(array $bar) { print_r($bar); }
}
class B extends class A {
public function foo(array $bar, string $baz) { print_r([$bar, $baz]); }
}
Is it now impossible to override / overload a class methods EVEN if there is no interface defined...
if there was an interface defined I'd appreciate that any subclass needs to conform to that
interface.. but otherwise the class is just a class and methods should be completely overridable and
overloadable. There are literally millions of cases where this may be required, and if you
don't think its a bug, then I'll raise another ticket and try get someone else with a
brain to look at this.
------------------------------------------------------------------------
[2015-12-15 08:46:29] chazmead89 at gmail dot com
If the parent class specifies an interface without specifying an interface.. then what is the point
in the Interface type?
------------------------------------------------------------------------
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
https://bugs.php.net/bug.php?id=71119
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Edit this bug report at https://bugs.php.net/bug.php?id=71119&edit=1
Thread (8 messages)