Rely on ClassInfo to retrieve all classes

[rskuipers]

We were frequently getting strange issues where getOwner() could not be properly resolved.
After some debugging I came to the following conclusion.

get_declared_classes() only returns a list of classes that were loaded by either being referenced by another class, or because that class was being analyzed.
So any extensions that were attached to a class that wasn't yet analyzed or otherwise referenced in the code and used $this->getOwner() would fail because the code would conclude the extension wasn't applied on any class.

By using ClassInfo::allClasses() we utilize the ClassManifest of SilverStripe which contains all classes defined.

This resolves quite a few headaches for us (we've been trying to track this down for a bit).

[mleutenegger]

It seems like there was a problem with the workflow. In the meantime workflow-definitions have been updated but Github seems to not allow me to re-run the checks. I know this sounds silly, but could you push a commit (e.g. a newline) so it is forced to rerun them?

[rskuipers]

@mleutenegger no worries! done.

[mleutenegger]

Interesting, it seems like the tests are failing because of the reverse of the problem you tried to fix 🤪 .

While ClassInfo::allClasses() returns all classes in the project, class_uses(...) does not know them and throws a warning which then kills the test runner. As (for obvious reasons) we can't really skip classes that do not exist, I wonder if there is a working solution using a mix of \ReflectionClass::getTraits() and the ClassInfo::subclassesFor(...) method.

Basically, instead of doing it like this

silverstripe-phpstan/src/Type/ExtensionReturnTypeExtension.php

Lines 131 to 146 in a4ccd20

	$classes = ClassInfo::allClasses();
	$result = array();
	foreach ($classes as $class) {
	$hasTrait = false;
	foreach ($classes as $subclass) {
	$hasTrait = false;
	foreach (class_uses($class) as $trait) {
	$hasTrait = $hasTrait || $trait == ClassHelper::Extensible;
	}
	if ($hasTrait) {
	$result[$subclass] = $subclass;
	}
	}
	}
	$result = array_values($result);
	return $result;

We do something like this:

$classes = ClassInfo::allClasses();
$result = array();
foreach ($classes as $class) {
    $reflection = new \ReflectionClass($class);
    $traits = $reflection->getTraits();
    if ( /* "Extensible" in $traits */ ) {
        foreach (ClassInfo::subclassesFor($class, true) as $subclass) {
            $result[$subclass] = $subclass;
        }
    }
}
$result = array_values($result); 
return $result; 

If you have the time to try it, that would be great

[mleutenegger]

additionally, I am not quite sure if this double-loop over the same class-list even leads to the correct result, as it would loop over the same class list twice, instead of actually filtering out subclasses of those using the Extensible trait.

silverstripe-phpstan/src/Type/ExtensionReturnTypeExtension.php

Lines 133 to 136 in a4ccd20

	foreach ($classes as $class) {
	$hasTrait = false;
	foreach ($classes as $subclass) {
	$hasTrait = false;