Add support for more PDOStatement fetch modes

[duskwuff]

The PDO::FETCH_CLASSTYPE and PDO::FETCH_PROPS_LATE flags aren't supported yet, as implementing them would require some way to read the value of an expression like PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE as the argument to PDOStatement::fetch(). This seems like something that might be useful down the road, but I'm hesitant to implement it just for this feature. :)

There are a few other really obscure fetch modes which aren't supported either, like PDO::FETCH_FUNC and PDO::FETCH_SERIALIZE. They're barely even documented and I'm not sure they even make sense to use outside of fetchAll(), so... whatever.

(in re. #2529)

[muglug]

Thanks!

I think PDO::FETCH_CLASS can use information from the second parameter, right?

[staabm]

Thanks!

I think PDO::FETCH_CLASS can use information from the second parameter, right?

Nope, I dont think so:
https://www.php.net/manual/en/pdostatement.fetch.php

PDO::FETCH_CLASS: returns a new instance of the requested class, mapping the columns of the result set to named properties in the class, and calling the constructor afterwards, unless PDO::FETCH_PROPS_LATE is also given. If fetch_style includes PDO::FETCH_CLASSTYPE (e.g. PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE) then the name of the class is determined from a value of the first column.

I guess you mixed it up with fetchObject()
https://www.php.net/manual/en/pdostatement.fetchobject.php

[muglug]

Ahh right yes, sorry.

[MarkusRodler]

The PDO::FETCH_CLASSTYPE and PDO::FETCH_PROPS_LATE flags aren't supported yet, as implementing them would require some way to read the value of an expression like PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE as the argument to PDOStatement::fetch(). This seems like something that might be useful down the road, but I'm hesitant to implement it just for this feature. :)

There are a few other really obscure fetch modes which aren't supported either, like PDO::FETCH_FUNC and PDO::FETCH_SERIALIZE. They're barely even documented and I'm not sure they even make sense to use outside of fetchAll(), so... whatever.

(in re. #2529)

I don't think that PDO::FETCH_FUNC is very obscure. It is acutally a really handy one. For example if you want to initialize a class with a private constructor. Then you can use FETCH_FUNC to call your static factory method instead.

Example:

// Repository.php
$query->fetchAll(PDO::FETCH_FUNC, [ValueObject::class, 'createFromDb']); // Will return an instance of the ValueObject class

// ValueObject.php
class ValueObject
{
    private function __construct(DateTimeImmutable $test) {}
    public static function createFromDb(string $test): self
    {
        return new self(new DateTimeImmutable($test));
    }
}

It would be very nice if psalm could support this case, too.