Question

Imagine i have 2 classes (i’ve simplified the logic here):

class Table {
    public function addRow (Row $row){
        $this->row = $row;
    }
    // lots of code
}
class Row {
    // lots of code
}

And i want to extend the table class to do something similar so i create 2 new classes:

class SpecialTable extends Table{
    public function addRow (SpecialRow $row){
        parent::addRow($row);
    }
    // lots of code
}
class SpecialRow extends Row{
    // lots of code
}

When i try to add a SpecialRow to a SpecialTable object i get a warning similar to:

PHP Strict standards:  Declaration of SpecialTable::addRow() should be compatible with that of Table::addRow() in /SpecialTable.php on line XX

Can someone help me here? Is this bad practice and i should code it differently? Or is it just a warning that i should ignore?

Many thanks for any suggestions / guidance.

Answer 1

You should probably use a name like SpecialTable::addSpecialRow() if you’re changing the argument type – otherwise SpecialTable doesn’t actually extend Table, it overloads it (which isn’t supported in PHP).

Based on your simplified example, it should be public function addRow(Row $row) since you just call the parent. Depending on what you’re actually doing to $row in that function, you could type-hint Row and check whether it’s a SpecialRow in code, or just use Row if you don’t need its Specialness.