Can Overriding Method Signatures Be Avoided in Strict PHP Standards?

Strict Standards Avoidance: Overriding Method Parameters

In PHP, strict standards enforce the adherence to predefined coding rules to ensure code reliability. One such standard prohibits overriding method parameters. Consider the following code:

<code class="php">class Foo
{
    public function bar(array $bar) {}
}

class Baz extends Foo
{
    public function bar($bar) {}
}</code>

Here, the overriding method in Baz (with a single parameter) differs in signature from the original method in Foo (which takes an array as an argument). As a result, PHP triggers a strict standard warning.

This violation stems from the Liskov Substitution Principle (LSP), an OOP design rule stating that a subtype (Baz) may seamlessly replace its supertype (Foo) without altering program behavior. In strong-typed languages, altering method signatures in a subtype would create method overloading, but in weakly-typed PHP, such distinction is impossible.

To ensure LSP compliance and avoid altering method behavior, strict standards prevent modifying method signatures in overriding methods. This warning serves as a reminder to maintain consistency between parent and child class methods, preventing potential bugs from method signature mismatches during method invocation.

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