Why PSR-0/4 are confusing, from my perspective

psr-autoloading.md

PSR-0 and PSR-4 are both PSR-Confusing

Phil Sturgeon asked everyone's opinion about deprecating PSR-0 and I was an ass and said they were both awful. I don't think that, but I think they're both about equally confusing from userland so it doesn't really matter to me. Phil had a great question https://twitter.com/philsturgeon/status/490659076096131072 about how they're confusing, and I needed more than a few tweets to explain.

I use PSR-0 and now some PSR-4 all the time for autoloading, although my experience is generally filling out composer.json "autoload" keys. Every single time I go to fill out "autoload": { "psr-0": I have to spend 5-10 minutes going back through docs trying to figure out how to designate the right path -> namespace match so that my files will load. In other words, neither is very intuitive. "What folders do I need to nest inside src? What do I have to repeat? What if I want to just include some util classes in my lib folder?"

I always assume I can just declare

{
  "autoload": {
    "lib/utils": "MyUtils"
  }
}

and get lib/utils/Thingy.php === <?php namespace MyUtils; class Thingy { and for some reason that never seems to work in either 0 or 4, and it's hard for me to ever remember why.

Compare that to the other language I write every day, JS in the node/commonJS format:

var corelib = require("core-lib");
var third = require("third-party-lib");
var myutil = require("./lib/myutil");

For whatever reason, this is just really straightforward. I never have to look anything up about this in any docs ever because it maps to how my brain thinks about the way files might be loaded--either you know where they are by default and I just require them by name, or I tell you where they are explicitly from where I'm requiring them. Sometimes I wonder if just going back to PHP require "./path/to/mylib" would be clearer and easier to reason about...

But anyway, I do think that autoloading in PHP has come a long way and that both 0 and 4 are solid standardizations that do the job they're trying to do while maintaining some tricky backwards compatibility for big frameworks that need it, but I just don't feel like one or the other is obviously better from a usability perspective. (Obviously there are probably many other perspectives to consider, I realize.)

The trouble here, is that a few different things are being confused.

{
  "autoload": {
    "lib/utils": "MyUtils"
  }
}

This looks like an attempt at writing a composer.json. Is that what you intended? Because if so, that has nothing to do with the PSR-0 or PSR-4 standard itself, right? Composer happens to use the rules, but is not part of it. They're often confused.

var corelib = require("core-lib");

Absolutely, some sort of package loading system in PHP would be amazing, much like Python or anything else.

This is "fault", or a lack of a feature of PHP itself. It is not something that the PHP-FIG have control over, but is something I'd certainly love to see some day.

If PSR-0 and PSR-4 are confusing based on this, then it is not really the fault of the specifications themselves.