1.2.1328. Use Instanceof

The instanceof operator is a more precise alternative to is_object(). It is also faster.

instanceof checks for an variable to be of a class or its parents or the interfaces it implements. Once instanceof has been used, the actual attributes available (properties, constants, methods) are known, unlike with is_object().

Last, instanceof may be upgraded to Typehint, by moving it to the method signature. instanceof and is_object() may not be always interchangeable. Consider using isset() on a known property for a simple check on objects. You may also consider is_string(), is_integer() or is_scalar(), in particular instead of !`is_object() <https://www.php.net/is_object>`_.

The instanceof operator is also faster than the is_object() functioncall.

<?php

class Foo {

    // Don't use is_object
    public function bar($o) {
        if (!is_object($o)) { return false; } // Classic argument check
        return $o->method();
    }

    // use instanceof
    public function bar($o) {
        if ($o instanceof myClass) {  // Now, we know which methods are available
            return $o->method();
        }

        return false; } // Default behavior
    }

    // use of typehinting
    // in case $o is not of the right type, exception is raised automatically
    public function bar(myClass $o) {
        return $o->method();
    }
}

?>

See also Type Operators and is_object.

1.2.1328.1. Suggestions

• Use instanceof and remove is_object()

• Create a high level interface to check a whole family of classes, instead of testing them individually

• Use typehint when possible

• Avoid mixing scalar types and objects in the same variable

1.2.1328.2. Specs

Short name	Classes/UseInstanceof
Rulesets	All, Analyze, CE, CI-checks, Changed Behavior
Exakat since	0.8.4
PHP Version	All
Severity	Major
Time To Fix	Quick (30 mins)
Precision	High
Features	instanceof
Examples	TeamPass, Zencart
Available in	Entreprise Edition, Community Edition, Exakat Cloud