[EA] Null pointer exception may occur here. False positive.

[Chemaclass]

Subject	Details
Plugin	Php Inspections (EA Extended), 4.0.7.1
Language level	PHP 7.4

I think this is related to https://www.giters.com/kalessil/phpinspectionsea/issues/1560 or at least, pretty similar (by @voku)

Current behaviour

When using "Person.ageNullable" property, then there is a complain about a possible null although the method Person->getName() has a non-nullable return type of /** @return Age */.

The reason seems to be that it's getting the return type from the property /** @var Age|null */ and not from the method /** @return Age */.

Expected behaviour

I would expect to don't have this warning of "Possible NULL" when the method has a specific non-nullable return type.

Environment details

This applies to all PHP versions. But especially from PHP >=7.4

The code used to reproduce the example

<?php declare(strict_types = 1);

class Age
{
    private int $value;

    public static function fromInt(int $age): self
    {
        if ($age < 0) {
            throw new \RuntimeException('Impossible');
        }
        $self = new self();
        $self->value = $age;
        return $self;
    }

    public function value(): int
    {
        return $this->value;
    }
}

class Person
{
    /** @var Age|null */
    private $ageNullable;

    /** @var Age */
    private $ageForced;

    public static function withAge(int $age): self
    {
        $self = new self();
        $self->age = Age::fromInt($age);
        return $self;
    }

    /** @return Age */
    public function getAge()
    {
        return $this->ageNullable;
    }
}

class MainExample
{
    public static function main(): void
    {
        $person = Person::withAge(28);
        $age = $person->getAge();

        self::printAge($age); # <---- THIS IS A FALSE POSITIVE
    }

    private static function printAge(Age $age): void
    {
        echo 'Age value: ' . $age->value();
    }
}

I'm sorry for the code, it's not ideal I know... but this is the quickest way to share the problem. Using real return types at level function is (unfortunately) not an option in this context. That's why I think it's a pretty nice edge case...

[mike-zukowski]

Exactly the same issue with older Symfony code:

abstract class ContainerAwareCommand extends Command implements ContainerAwareInterface
{
    /**
     * @var ContainerInterface|null
     */
    private $container;

    /**
     * @return ContainerInterface
     *
     * @throws \LogicException
     */
    protected function getContainer()

then in any extending class:

$this->getContainer()->getParameter('kernel.environment')

ends with Null pointer exception may occur here. The plugin should respect the annotations if you ask me as this is the ultimate source of truth provider by the developer.

[alsii]

The same thing occurs in Doctrine:

        $criteria = Criteria::create()
            ->where(Criteria::expr()->eq('active', 1)) // <---- THIS IS A FALSE POSITIVE
        ;

Doctrine Code:

    /**
     * Returns the expression builder.
     *
     * @return \Doctrine\Common\Collections\ExpressionBuilder
     */
    public static function expr()
    {
        if (self::$expressionBuilder === null) {
            self::$expressionBuilder = new ExpressionBuilder();
        }

        return self::$expressionBuilder;
    }