PHP 8 union types, [presumably same for 8.1 intersection types].

[sjokkateer]

Bug Report

Q	A
Version(s)	3.7.x

Summary

When trying to create an object that depends on a union type in its constructor, a call to Injector::create() results in an error.

Current behavior

The Injector::class forwards the resolveParameters() call to the DependencyResolver::resolveParameters() method, which, at L#280 makes a call to Parameter::getType(). Within this method, a call is made to the underlying object's ReflectionParameter::getType() method is made. The returned object by getType() is a ReflectionUnionType::class, which has no method getName() defined, and hence, it crashes the program due to L#63.

The error message: Error: Call to undefined method ReflectionUnionType::getName()

How to reproduce

Settings: PHP 8.0.19 (cli)

Class definition:

class Foo
{
    public function __construct(private string|Stringable $s)
    {
    }

    public function getS(): string|Stringable
    {
        return $this->s;
    }
}

Test case:

public function testCreateClassWithUnionTypeParameterAsConstructorArgument(): void
{
    $injector = new Injector();

    $s       = 'Hello, World';
    $foo     = $injector->create(Foo::class, ['s' => $s]);
    $actualS = $foo->getS();

    $this->assertEquals($s, $actualS);
}

Expected behavior

An instance of Foo::class constructed with the property $s set to the string value 'Hello, World'.

PS

I am sorry if this is not considered a bug, but I did not know where to otherwise post this matter. Please let me know what you think of the above stated.

[Ocramius]

This is kinda like a PHP 8.0 feature request. PHP 8.1 will have similar problems with intersection types.

I think that digging for ReflectionParameter#getType() usages is the start of a researcher here: phpstan/psalm checks being improved would highlight these regressions caused by the language.

[sjokkateer]

I see and thanks for your swift reply. Would you like me to modify this issue's format into that of a feature request, create a new issue for this matter, or are there some other steps I should take?

[Ocramius]

IMO just PR if you do any work on supporting union or intersection types 😁

[Ocramius]

What I can imagine the logic to be:

• For a union type, search for all types in the union in the DIC
  • if one (and only one) matches, use that
  • If multiple services match, throw an exception that explains the ambiguity
• For an intersection type, do the same as above, but:
  • All service instances must be checked for compatibility with the intersection type
    • If none matches, throw an exception
    • if multiple natch, throw an exception
    • If exactly one matches, use that