As I am familiar with those interceptions, I tend to point out some dirty
hacks
when reflection tells you property exists while getting notice on set, see
https://3v4l.org/VDMHm
<?php
class Foo
{
public $bar = 'bar';
public $baz = 'baz';
}
class FooHack extends Foo
{
public function __construct(Foo $wrapped)
{
unset($this->bar);
}
}
$foo = new FooHack(new Foo);
$reflectionFooBar = new \ReflectionProperty(Foo::class, 'bar');
var_dump((new ReflectionClass(Foo::class))->getProperties());
var_dump($reflectionFooBar->getValue($foo));
var_dump(
property_exists(FooHack::class, 'bar'),
property_exists($foo, 'bar')
);
Funny PHP7 has different behaviour from 7.0.7 - 7.1 with raising a notice.
I may be just looking for dirty example without purpose right now so, don't
listen to me.
But I do feel like this could bring someone crazy when something should
exists while it's not.
Those property_exists($foo, 'bar') shouldn't return false in that example?!
2017-01-16 10:17 GMT+01:00 Marco Pivetta <ocram...@gmail.com>:
> On Mon, Jan 16, 2017 at 9:49 AM, Michał Brzuchalski <
> mic...@brzuchalski.com> wrote:
>
>> Hi Marco,
>>
>> 2017-01-16 0:27 GMT+01:00 Marco Pivetta <ocram...@gmail.com>:
>>
>>> Hi Wes,
>>>
>>> This has been discussed before, and it's currently used to intercept
>>> access
>>> to properties. Since we don't have property accessors (sigh), the code
>>> (simplified version) would look like following:
>>>
>>> class Foo
>>> {
>>> public $bar = 'baz';
>>> }
>>>
>>> class FooInterceptor extends Foo
>>> {
>>> private $wrapped;
>>> public function __construct(Foo $wrapped)
>>> {
>>> $this->wrapped = $wrapped;
>>> unset($this->bar);
>>> }
>>> public function __get(string $name)
>>> {
>>> var_dump('reading ' . $name);
>>> return $this->wrapped->$name;
>>> }
>>> }
>>>
>>> $foo = new FooInterceptor(new Foo);
>>>
>>> var_dump($foo->bar);
>>>
>>> You can see a working example at https://3v4l.org/UtugD
>>
>>
>> There is one more thing might be confusing - reflection tells there still
>> exists bar property after unset while it's realy not.
>> For example https://3v4l.org/NAg1l
>>
>> $class = new ReflectionClass(FooInterceptor::class);
>> $property = $class->getProperty('bar');
>> var_dump($property); // still exists while actually being unset may cause
>> errors
>>
>> I'm sticking to extending class without magic _get method implemented.
>>
>>
>>>
>>>
>>> This behavior is protected from regressions since PHP 5.4, but has been
>>> working since 5.0:
>>> https://github.com/php/php-src/blob/cd2b462a2742c79256668d47
>>> 36644e34573c33d9/tests/classes/unset_properties.phpt
>>>
>>> We can most probably get rid of this weird behavior once property
>>> accessors
>>> are in the language.
>>>
>>> Greets,
>>>
>>> Marco Pivetta
>>>
>>> http://twitter.com/Ocramius
>>>
>>> http://ocramius.github.com/
>>>
>>> On Mon, Jan 16, 2017 at 12:20 AM, Wes <netmo....@gmail.com> wrote:
>>>
>>> > Hello elephpants.
>>> >
>>> > Currently PHP allows explicitly declared fields (eg public $foo = 10;)
>>> to
>>> > be removed entirely through unset (eg unset($obj->foo)).
>>> >
>>> > Now that isn't really an issue as properties in php are currently
>>> untyped
>>> > and therefore nullable; at worst you would get a notice. But it would
>>> > become an issue with typed fields... that might get a second chance
>>> sooner
>>> > or later.
>>> >
>>> > But regardless of that, it looks very strange to me that this is
>>> allowed
>>> > for fields that are explicitly declared. I think unset() should set the
>>> > field to null if it's declared in the class, and remove the field
>>> > altogether only if it was defined dynamically.
>>> >
>>> > On the other hand, this is just one of many ways of hacking php that
>>> just
>>> > exist and we accept / don't care because we have faith in other people
>>> not
>>> > doing nasty stuff with our code. This might sound ironic it is
>>> actually not
>>> > :P
>>> >
>>> > However, I am curious: what you think about this? Should PHP do
>>> something
>>> > in regard? Should this continue to work like it does now? Why do you
>>> feel
>>> > it should do the one or the other?
>>> >
>>>
>>
> Hi Michał,
>
> Reflection will also trigger `__get` in this scenario, which is expected
> and was also reverted multiple times in "fixes" that worked around or
> forgot to call the property access guards.
>
> class Foo
> {
> public $bar = 'baz';
> }
>
> class FooInterceptor extends Foo
> {
> private $wrapped;
> public function __construct(Foo $wrapped)
> {
> $this->wrapped = $wrapped;
> unset($this->bar);
> }
> public function __get(string $name)
> {
> var_dump('reading ' . $name);
> return $this->wrapped->$name;
> }
> }
>
> $foo = new FooInterceptor(new Foo);
>
> $reflectionFooBar = new \ReflectionProperty(Foo::class, 'bar');
>
> var_dump($reflectionFooBar->getValue($foo));
>
> See https://3v4l.org/6JtWT for a working example.
>
> You can see https://github.com/Ocramius/ProxyManager/tree/
> cce5477857504997baf3168974b8f1283516a686/tests/language-feature-scripts
> for
>
> As I already mentioned, this hack is currently necessary to make property
> access interception transparent, which is common for most AOP-oriented
> code. We need an alternate approach to make this happen, before such a
> feature can be dropped.
>
> Marco Pivetta
>
> http://twitter.com/Ocramius
>
> http://ocramius.github.com/
>
--
regards / pozdrawiam,
--
Michał Brzuchalski
about.me/brzuchal
brzuchalski.com
