newLazyProxy($closure) throws error on $closure result null, but can't capture it.

[procodix]

Description

The following code:

try {
	class Test {
		public string $Foo = 'Bar';
	}
	$proxy = new ReflectionClass(Test::class)->newLazyProxy(fn() => null);
	$proxy->Foo;
} catch (Throwable $x) {
	// do something...
}

Resulted in this output:

Error: Lazy proxy factory must return an instance of a class compatible with Zok\System\Test, null returned

But I expected instead:

• allow "null" to be returned from the closure, so that its signature be like: function($ghost):?object
• allow the error thrown to be captured and instead return null, and replace the proxy shell with null

BTW this would could collapse ghosts and proxies to a single lazy concept, allowing to return

• a previously empty shell object, now filled with
• a freshly created object
• null. This is important if -for example- a database lookup returned no result

### PHP Version

```plain
PHP 8.4

Operating System

macOS

[iluuu1994]

allow "null" to be returned from the closure, so that its signature be like: function($ghost):?object

How would that work? The proxy proxies property accesses and method calls to the underlying object. What do you proxy to if there is no underlying object?

allow the error thrown to be captured

That works for me. https://3v4l.org/FknU4#v8.4.10

[procodix]

The proxy works as placeholder. And it is a one-time use object. Who says, it has to stay active and mediate calls to the real instance? In contrary, as soon, as the real instance surfaces, the proxy is obsolete.

As an often-mentioned use case, lazy proxy can be used for late-db-queries, on-access only. However, this can return null, and therefore it should be possible.

Example: Blogpost model object contains link to Author. After the author is deleted, the proxy will return null.

My example ends up here:

php-src/Zend/zend_lazy_objects.c

Line 501 in 2645663

zend_type_error("Lazy proxy factory must return an instance of a class compatible with %s, %s returned",

[procodix]

Please check revised example: https://3v4l.org/2bA0l#v8.4.10

The exception does not occur, if you delete the "echo" , thus skipping the lazy initiative.

<?php

class Test {
	public string $Foo = 'Bar';
}

function Load(string $class, mixed $primary):?object {
	try {
		return new ReflectionClass($class)->newLazyProxy(fn() => null);
	} catch (\Throwable $x) {}
	return null;
}

//this works, not triggering lazy init...
Load(Test::class, 1);
//this fails.
echo Load(Test::class, 2)?->Foo;

[iluuu1994]

Well yeah, the purpose for lazy proxies is to be lazy. You should not be constructing a lazy object if the object may be null. In that case, even simple conditionals in your code are flawed. E.g. $blog->author !== null would say true, but it might not actually be there, you'd only know once you load the object. That can't work, and it's definitely not how lazy objects were designed according to the spec. ¹

Who says, it has to stay active and mediate calls to the real instance?

As mentioned above, the spec.

Footnotes

1. https://wiki.php.net/rfc/lazy-objects ↩

[procodix]

Then what is their use? I thought they were supposed to defer the expensive operation of creating (proxy) or filling (ghost) an object to the call time. But they don't cover the common case where there is no valid object found. And the exception that is thrown then, cannot be catched at call time/site, but only at setup time. I don't see way to handle a failed load operation.