title: PHP Conditionals: is_null($someVariable) vs. $someVariable === 0
body: <p>I just debugged a problem I had to the root I mention down here:</p>
  
  <p>The first conditional is true;
  The second conditional does not execute;</p>
  
  <p>Why does the 2nd conditional not execute?</p>
  
  <pre><code>$someVariable = 0;
  
  if ( $someVariable === 0 ) var_dump('worked');
  
  if ( is_null($someVariable) ) var_dump('worked too');
  </code></pre>
  
  <p>I think I saw it working in some 'legacy' code, but am not sure about it. </p>