Comments on: Signs your PHP needs refactoring

By: Dave Doolin

Dave Doolin — Wed, 03 Jun 2009 18:57:00 +0000

I’m working through reverse engineering my first php application right now. The code is… interesting…

I was prepared to accept something like “php is different” but after really digging in, no, php is just the same as every other programming language.

Part of it is php makes it easy to write a lot “working” code without knowing how anything actually works. Effective refactoring means you have to understand stuff like “scope.” Boring.

By: sole

sole — Wed, 05 Mar 2008 19:34:28 +0000

O-M-G

I’m surprised you’ve survived – you’re a tough one!!!!!

The people which had written that … shouldn’t have set their fingers in the keyboard ever!

this makes for a true daily WTF, you should send it to them :-)

By: RE-coder

RE-coder — Wed, 05 Mar 2008 19:03:57 +0000

You missed a really obvious one, probably because it’s SO obvious – but it’s been a major headache in the million-line application I’m refactoring now. (OK, that was a little bit of an exaggeration; I didn’t actually start with a million lines, only 931,327. Close enough.)

Far, FAR worse than 300-line switch statements are 1000+ line nested if/if/elseif/else blocks. Try this one on for size (a real example taken from production code, just greatly simplified for clarity):

if ($a) {

     if($b) { } // 200+ lines

     else if ($c) { } // 100+ lines

     else doDefault();

} else if ($i) {

     if($j) // 300+ lines

     else if($c) { } // 100+ lines

     else if ($k) { 

          if($l) { } // 250+ lines

          else if($m) // 75 lines

     } 

} else if ($w) {

     if($x) // { } 200+ lines

     else if ($y) { } // 150 lines

}

else { 

    doDefault();

}

if($nothing_has_been_done_yet) { doDefault(); }

I tried to make the major problem there as obvious as possible. Condition
$c actually equated to ‘user does not have permission to view this page’.
However, there were certain conditions under which forbidden users were
inadvertently allowed in; for instance, when ($i && $j) equated to true,
or when ($w && !$x && !$y). This was a definite bug, one that had never
before been identified. And it would’ve been impossible find and fix
within the 1000+ lines of code without refactoring it.

My rewrite of that code ended up something like the following:

switch($foo) {

    case 'c': displayAccessForbiddenPage(); exit;

    case 'b': doB(); break;

    case 'j': doJ(); break;

    case 'k': doK($l,$m); break;

    case 'x': doX(); break;

    case 'y': doY(); break;

    default: doDefault();

}

I think it’s inarguable that the refactored code is far easier to read, understand, debug and modify than the original version.

Please pass the Excedrin, sole. Thank God I’m almost done with this beastie. I just fervently wish that the people who’d written this application had read your article before ever setting fingers to keyboard.

By: Ve

Ve — Sat, 13 Oct 2007 10:54:29 +0000

Great work! In particular, I’m glad you mentioned the “not-so-obvious” and “not-so-widely-discussed” (hence, easy to forget) ones – “Everything’s an array” and especially “You have to modify too many files”. Also, I second the advice on having E_NOTICE turned on while developing.

By: Jan Pieter Kunst

Jan Pieter Kunst — Fri, 12 Oct 2007 18:52:32 +0000

Cups wrote: “Still, one nagging question that I haven’t chased down to my full satisfaction – why is a Constant not a Global then?”

A constant is global, but it’s also immutable. So there is no need to worry about “keeping track of who’s modifying what”.