PHP Coding styles return; in switch/case

Question

Hi ,

we're trying to implement new coding style guidelines for our team, the php codesniffer is printing an warning on switch case statements when no "break" is found like:

switch ($foo) {   
    case 1:
      return 1;   
    case 2:
      return 2;   
   default:
       return 3; 
}

is there any good reason to use :

   switch ($foo) {
       case 1:
         return 1;
         break;
   }

?? the break is never reached ?

Answer 1

From the PHP manual (http://us3.php.net/manual/en/control-structures.switch.php) :

PHP continues to execute the statements until the end of the switch block, or the first time it sees a break statement. If you don't write a break statement at the end of a case's statement list, PHP will go on executing the statements of the following case. For example:

<?php
switch ($i) {
    case 0:
        echo "i equals 0";
    case 1:
        echo "i equals 1";
    case 2:
        echo "i equals 2";
}
?>

Here, if $i is equal to 0, PHP would execute all of the echo statements! If $i is equal to 1, PHP would execute the last two echo statements. You would get the expected behavior ('i equals 2' would be displayed) only if $i is equal to 2. Thus, it is important not to forget break statements (even though you may want to avoid supplying them on purpose under certain circumstances).

Answer 2

I am not an expert in perfect coding but I think the validator would prefer something like that

switch ($foo) {   
    case 1:
      $ret =  1;   
      break;
    case 2:
      $ret = 2;
      break;   
   default:
       $ret = 3

}
return $ret

I think using return in case statement to break the flow of the code is not really a best practice. So that's why the validator say there is no break ...

For your question about at category, I don't know ... sorry

Answer 3

It's perfectly valid to leave out the break when you return from a switch.

But it's fairly common practise to add explicit breaks to every case as a defensive programming practise.

switch ($foo) {
    case 1:
        return 1;
        break;

    case 2:
        return 2;
        break;
}

The idea is that should you later change your code in case 1 and remove the return statement, you could forget to add a break.

That would accidentally cause program flow to fall through to case 2.

switch ($foo) {
    case 1:
        somethingDifferent();

    case 2:
        return 2;
        break;
}

Falling through case statements is slightly unusual and you should add a comment to your code when you do it to show that it's intentional.

switch ($foo) {
    case 1:
        somethingDifferentAndWeWantToDoCase2AsWell();
        // fallthrough

    case 2:
        return 2;
        break;
}

As with many defensive programming practises you've got to balance whether the code bloat - which potentially clutters your code and make it less readable - is worth it or not.