Differentiate null from undefined on Symfony PHP - php

Question

For example, I have the following entity Street:
id: 1
name: Street name
house number: 1
house number addition (nullable): 'A'
And the following graphql mutation:
mutation updateStreet ($input: UpdateStreet!) {
updateStreet(input: $input) {
id
name
houseNumber
houseNumberAddition
}
}
And the input:
{
"input": {
"id": 1,
"name": "Changed Name",
}
}
The problem is with the nullable field ("houseNumberAddition") because it will also be changed to null even if I don't want that.
The question is how can I differentiate between 'null' and 'undefined' in Symfony PHP ?
This is the command:
#[GQL\Input('UpdatePartner')]
final class UpdatePartner
{
#[GQL\Field(type: 'Guid!')]
#[Assert\NotBlank(message: 'Partner guid is required')]
#[Assert\Uuid(message: 'Partner guid is not a valid UUID')]
public Uuid $guid;
#[GQL\Field(type: 'String')]
public ?string $street;
#[GQL\Field(type: 'String')]
#[
Assert\Length(
max: 255,
maxMessage: 'House number exceeds limit of 255 characters'
)
]
public ?string $houseNumber;
#[GQL\Field(type: 'String')]
#[
Assert\Length(
max: 255,
maxMessage: 'House number addition exceeds limit of 255 characters'
)
]
public ?string $houseNumberAddition;
public function guid(): Guid
{
return Guid::fromString($this->guid->toRfc4122());
}
}

Answer 1

You can ignore type like this
#[GQL\Field(type: '?String')] OR [GQL\Field(type: 'null|String')]
#[
Assert\Length(
max: 255,
maxMessage: 'House number addition exceeds limit of 255 characters'
)
]
public ?string $houseNumberAddition;