Revert #1741 - \DOMElement::$attributes is never null

[Jean85]

See phpstan/phpstan#13076

This reverts #1741
From the PHP docs: https://www.php.net/manual/en/class.domnode.php#domnode.props.attributes

A DOMNamedNodeMap containing the attributes of this node (if it is a DOMElement) or null otherwise.

So, on \DOMElement it's correct to override and mark it as not nullable.

[VincentLanglet]

I agree with this PR @isfedorov, sorry my mistake

[isfedorov]

I'm sorry but I'm not sure I've got it.

A DOMNamedNodeMap containing the attributes of this node (if it is a DOMElement) or null otherwise.

So as I understand this, this property can contain null if the object isn't a DOMElement. But even if the object is a DOMElement reflection still shows that the type of property is nullable.
https://3v4l.org/HPtTl
Could you please clarify?

[VincentLanglet]

I'm sorry but I'm not sure I've got it.

A DOMNamedNodeMap containing the attributes of this node (if it is a DOMElement) or null otherwise.

So as I understand this, this property can contain null if the object isn't a DOMElement. But even if the object is a DOMElement reflection still shows that the type of property is nullable. 3v4l.org/HPtTl Could you please clarify?

The logic behind is kinda

get_type($dom->attributes) = $dom instanceof DOMELement ? DOMNamedNodeMap : null;

Indeed seems like the reflection is telling the property might be nullable, but it's untrue for a DOMELement.

• The property is initialized
• The property is read only so cannot be re-set to null

see https://onlinephp.io/c/7b879

[isfedorov]

The property is read only so cannot be re-set to null

Readonly isn't related to nullability. If you assign a DomNamedNodeMap instead of null the script will also fail, will not it? And the fact that if an object is of type DomElement then property contains objects of DOMNamedNodeMap but not null doesn't make the property not nullable.

[VincentLanglet]

The property is read only so cannot be re-set to null

Readonly isn't related to nullability. If you assign a DomNamedNodeMap instead of null the script will also fail, will not it? And the fact that if an object is of type DomElement then property contains objects of DOMNamedNodeMap but not null doesn't make the property not nullable.

Sure

But

• When the object is DomElement, the property is initialized (so not null)
• You cannot set null to this property (because it's readonly)

This means that $domElement->attributes is never null, no ? And that's the meaning of the sentence

A [DOMNamedNodeMap](https://www.php.net/manual/en/class.domnamednodemap.php) containing the attributes of this node (if it is a [DOMElement](https://www.php.net/manual/en/class.domelement.php)) or [null](https://www.php.net/manual/en/reserved.constants.php#constant.null) otherwise.

• When it's a DOMElement it's a DOMNamedNodeMap
• When it's a DomNode which is not a DOMElement, it's nul
• So when it's "just" a DomNode, it's DOMNamedNodeMap|null

[VincentLanglet]

How to help moving things @isfedorov @Jean85 ? I feel like the discussion is stucked

[isfedorov]

@VincentLanglet I completely understand the reasoning of this change but what I don't like about this change is that we are trying to align stubs with actual runtime value instead of PHP native signature. What will happen if PHP implementation changes the default assigned value of property to null in DomElement implementation? The signature of the property will remain the same as it is at the moment, right? PhpStorm will not give you a warning that property can be null, but since the actual value will be null you can easily get an NPE in runtime. But as far as I can see this issue produces a lot of noise by other linters so let's make this change. The only thing that should be fixed additionally - type in LanguageLevelTypeAware attribute.

[VincentLanglet]

Oh indeed.

@Jean85 Can you change

#[LanguageLevelTypeAware(['8.1' => 'DOMNamedNodeMap|null'], default: '')]

to

#[LanguageLevelTypeAware(['8.1' => 'DOMNamedNodeMap'], default: '')]

?