Thursday, 19 June 2008

Good Things are good things....aren't they?

Anybody who's worked with me over the last 20 years or so knows that I generally evangelize conforming to standards when they exist, are relevant and widely agreed on. As the famous quote from Andrew Tanenbaum (in Computer Networks, 2/e, p. 254) reminds us, "The nice thing about standards is that you have so many to choose from." When "standards" are used to promote vendor agendas (e.g., Microsoft force-feeding OOXML to a hapless ISO) or when they go against the common sense built up through hard-won experience by practitioners. And when multiple standards for a product or activity exist, and those standards are each widely used by various users (who could have chosen other alternatives), and when those standards conflict with each other in important ways that can't be amicably resolved, then those "standards" cause reasonable people to not merely question their validity, but, too often, the entire concept of "standards".

As any developer who's worked in more than one shop, or sometimes even on more than one project in a shop, knows, coding standards are sometimes arbitrary, often the prizes and products of epic bureaucratic struggle, and (in the absence of automated enforcement such as PHP CodeSniffer) often honored more in the breach than the compliance. What makes things even more "fun" is conflicting standards. It's not all that unusual for a company to contract out for development work, specifying that their coding standards be complied with (since they're the customer and they're going to maintain, or control maintenance of, the code). If the contractor has their own set of standards that conflict with the customer's, then problems arise with internal process compliance, customer involvement and final delivery. It can be — and too often is — a sorry mess. Simple code reformatting problems can be taken care of with a pretty-printer program; oftentimes, though, one sees entire programs (which have to be debugged, documented and maintained) developed just to "translate" one format to another. Many shops just give up, declare the project to be an exception or exemption from their own internal standards and processes, and try to conform to the customer's demands. "Try to", since their developers, both writing and reviewing the code, are going to be fighting against it tooth and nail because it just "feels wrong".

This whole rant was inspired by reading through yet another coding-standard document; this one the Zend Framework PHP Coding Standard. One item in particular struck me as counter-intuitive. In Item B.2.1.1, PHP File Formatting — General, it says:

For files that contain only PHP code, the closing tag ("?>") is never permitted. It is not required by PHP. Not including it prevents trailing whitespace from being accidentally injected into the output.

Experienced PHP developers are quite likely to have problems with this, not least because it conflicts with earlier behavior of the PHP interpreter and with tools that expect well-formed code. This is one of the oddities which tools like the aforementioned PHP CodeSniffer need to take into account. (There are other, more blatant "yellow flags"

If you're in a shop which takes standards seriously, uses PEAR code and uses the Zend Framework, your code review meetings are likely quite interesting.

  • "OK, we're going to look at foodb.class.php first, and then the others I mentioned in the email yesterday."
  • "Which standard does it use?"
  • "Well, it ties in with PDO, so it ought to follow the PEAR standard, right?"
  • "OK, that sounds reasonable."
As the meeting continues...
  • "Hey, what's this at the end of omnibar.class.php? There's no 'close-PHP' tag! If we start using the code-search Wiki plugin that the Bronx Project folks keep raving about, it's not going to like that...."
  • "Oh, yeah, but that's because  it uses all this Zend Framework stuff, so we use Zend's coding conventions... see that comment at the top about how to run CodeSniffer?"
  • "Riiiiight...."

and so on. Weren't process and standards supposed to make development easier and more reliable?

I agree with the sentiment, apocryphally attributed to one or another of numerous software gurus, that, in the presence of otherwise adequate and sufficient standards, we shouldn't be so "egotistical" as to think developing a "better" standard than others already have is worth our time; take what's already out there, adapt as necessary, and move forward. The trick, of course, is in evaluating that condition, "otherwise adequate and sufficient." Also, since our craft is (hopefully) continuing to advance and adopt standard patterns for things done before, striking out on your own (after careful consideration) demands that the question be revisited from time to time. What are other development groups using (broadly) similar techniques to solve (broadly) similar problems using? Is a consensus forming, and do we have anything useful to say about it? Or has a single standard already taken hold, and we can take advantage of it (at least for new or reworked code)?

Code analyzers like lint and PHP CodeSniffer can be amazingly useful. But for them to function as standard/policy enforcement tools, there must be a standard, or a small group of similar standards for them to enforce. When development teams have to juggle between incompatible standards, it discourages them from following any standards. And in that direction lie... the 1970s.

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