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Carsonbot

@derrabus, thank you for the review.

I agree that currently extractFromDefaultValue() knows more than only how to get the type from the default value. I did that because after PHP 7.4 it's no longer possible to correctly get property nullability from the default value.

Before this version, I tried to copy nullability from the extractFromReflectionType() result, but we can't do it since Type objects are not editable.

Then I was thinking about the following code, but it's harder to understand and we would also need to change extractFromDefaultValue() method arguments. And even more, currently, we know that a nullability of all Types in the $fromReflectionType is the same, but probably it can change in the future, so using the nullability of the first one is not the best option.

public function getTypes($class, $property, array $context = []): ?array
{
    ...
    $isNullable = false;
    $fromReflectionType = null;
    if (\PHP_VERSION_ID >= 70400) {
        try {
            $reflectionProperty = new \ReflectionProperty($class, $property);
            $type = $reflectionProperty->getType();
            if (null !== $type && $fromReflectionType = $this->extractFromReflectionType($type, $reflectionProperty->getDeclaringClass())) {
                $isNullable = isset($fromReflectionType[0]) && $fromReflectionType[0]->isNullable();
            }
        } catch (\ReflectionException $e) {
            // noop
        }
    }

    if ($fromDefaultValue = $this->extractFromDefaultValue($class, $property, $isNullable)) {
        return $fromDefaultValue;
    }

    if ($fromReflectionType) {
        return $fromReflectionType;
    }

    return null;
}

Another solution would be to replace part of the current version of getTypes().

...
if ($fromDefaultValue = $this->extractFromDefaultValue($class, $property)) {
    return $fromDefaultValue;
}

if (\PHP_VERSION_ID >= 70400) {
    ...
    return $this->extractFromReflectionType($type, $reflectionProperty->getDeclaringClass())) {
    ...
}

return null;

With

...
if ($fromPropertyDeclaration = $this->extractFromPropertyDeclaration($class, $property)) {
    return $fromPropertyDeclaration;
}

return null;

and

private function extractFromPropertyDeclaration(string $class, string $property): ?array
{
    // calculate nullability
    // try to get from the default value
    // try to get from the property type, if PHP >= 7.4
    // else null
}

What do you think about these solutions?

Okay, but if we have a typed property – why would we want to look at the default value at all? Wouldn't it be enough to prioritize the property type over the default value when extracting type information? Or am I missing something?

I did some research on why typehint extraction is at the end. Typehint support was initially added in #34557, and it had the highest priority. And then in #38041 it was moved to the end of the method. After this issue was merged, in one of the comments, issue #38416 was mentioned.

I'm not sure if in this issue we should focus on property type priority versus constructor, mutator, and accessor. But I believe we can change the code so it uses property typehint on PHP 7.4 (and default value if there's no typehint) and a default value for older versions.

I don't think we're missing something, it's not possible to have a default value different from typehint.

I did some research on why typehint extraction is at the end. Typehint support was initially added in #34557, and it had the highest priority. And then in #38041 it was moved to the end of the method. After this issue was merged, in one of the comments, issue #38416 was mentioned.

I'm not sure if in this issue we should focus on property type priority versus constructor, mutator, and accessor. But I believe we can change the code so it uses property typehint on PHP 7.4 (and default value if there's no typehint) and a default value for older versions.

I don't think we're missing something, it's not possible to have a default value different from typehint.

I would like to take this opportunity to discuss this priority if possible. In my point of view #38041 introduced a BC break as serializer started having a different behaviour, and currently this in an impediment for me to update some of my projects, as described in #38416. Do you think we could change this order? I'm available to help with that

@dpinheiro I understand that the issue you've mentioned is important to you. But please let's leave the discussion on that ticket.

Thank you @shiftby.