How to make an update to base class less demanding on updating derived classes?
<p>this is for PHP:</p>

<p>The following scenario has been troubling me and I was wondering if anyone know a good strategy or solution.  My problem is the following:</p>

<pre><code>class Foo {
    public function doSomething() { // do something }
}

class Bar extends Foo {
     public function doSomething() { // do something else }
}
</code></pre>

<p>and let's say I have several other classes extending from Base but simply inherit doSomething().  The problem is if I need to make change to Bar::doSomething(), and need to update wherever it is referenced throughout the project, it won't be a simple job to search for occurrences of this particular function from this particular class.</p>

<p>How can I make life easier?  is there a design pattern that addresses this type of scenario?</p>
