Clearer Connection return types for affectedRows

[Seldaek]

Q	A
Type	improvement
Fixed issues	Alternative to/closes #5317

Summary

Per

dbal/src/Connection.php

Lines 1157 to 1160 in 83f779b

	return $result->rowCount();
	}
	return $connection->exec($sql);

the two ways executeStatement can return is via Result::rowCount and DriverConnection::exec but those two have an int return type, so it is currently impossible for executeStatement to return a string.

[Seldaek]

Found some problems in PHPStan fixed in phpstan/phpstan-src#1116 - similar issues are present in Psalm still but I'd rather not waste more time if this change isn't going to be accepted, so waiting for feedback first.

[morozov]

This is by no means acceptable. The library must not alter the data returned by the underlying driver in order to fit it into its own API which is incorrectly defined.

[derrabus]

What would be the alternative? Right now, if the number of affected rows is larger than PHP_INT_MAX and thus returned as a string by ext-mysqli, we will run into a TypeError here.

https://3v4l.org/03d4D

[morozov]

The return type should be int|string as it is in 4.0.x:

dbal/src/Driver/Mysqli/Connection.php

Line 60 in 8622d1d

public function exec(string $sql): int|string

[derrabus]

Understood, but don't we need a solution for DBAL 3 as well? After all, this is our maintained branch. Raising type errors seems like a mistake to me.

[morozov]

As discussed in #5317 (comment), it seems acceptable to remove the int return type declaration in 3.x since it's invalid.

[derrabus]

Okay, let's do that.