The Mindset

A couple of weeks ago I wrote about code which doesn’t deserve to be maintained. I received a lot of comments on this post. Many of them argued that unlike tangible goods, code does not decay. Some people referred me to Joel Spolsky’s article, saying that throwing away code which was already tested and used on the field is never a good economic decision.

In my response to these comments I clarified:

“If you get a piece of code and you assume it was well taken care of, you might be… well, wrong. That’s why you have to check. Saying that any piece of existing code is better than a new one doesn’t make sense. If, for example, the previous owners of the code did a lousy maintenance job, you might end up with code that requires you to invest weeks of work for each small change. You can try refactoring that mess, but this is not always possible or cost-effective.

Joel’s article and your comments are 100% right in an ideal world where most of the code out there is reasonably maintained. I’m not sure this is the reality we all work in. But in any case, it’s better not to assume anything and just make sure you check the status of the code before making a decision.

I don’t like black and white rules. Unlike Joel, I try not to use phrases that begin with “Never…” or “Always…”. Just keep your mind open to the option that sometimes a rewrite is better than refactoring.

Of course, you should do it wisely. Don’t wake up one day and throw away 500K lines of code. Do it incrementally and with proper safety nets. But keep in mind that this is a valid option.”

Then, a couple of days ago I came across this paragraph in Jerry Weinberg’s classic book Quality Software Management Volume 1:

“In time, existing code may even come to have a negative quality, meaning that it would be cheaper to develop new code than attempt to keep repairing the old. Many pattern 1 and pattern 2 organizations are holding large inventories of negative quality software, but usually they are unaware of that fact. Or if they are aware, they are so unsure of their ability to develop new code that they continue to limp along patching ever more pitiful and expensive systems.”

Maybe it’s just me, but this sounded awfully familiar. I just couldn’t believe I read this paragraph only after writing my post. Well, there you have it. I guess you should keep your options open, and keep in mind that sometimes starting over again is the right thing to do.

This entry was posted on Sunday, December 10th, 2006 at 11:33 am and is filed under Code Quality, Refactoring. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.