When “Agile”, “Dynamic” and “Typeless” Become a Hindrance.

In recent years, I’ve seen the apparent rising popularity of “Agile” programming, powered by “dynamic” languages such as “Ruby”. While these things seem warm and fluffy at first, in the long term with large projects, they really can become a difficult beast to control.

Let’s take “Ruby on Rails” as an example. I was recently tasked with upgrading our version of Rails from 1.2.3 all the way up to 2.3.2, no easy task to be sure. We decided that a gradual, version-by-version upgrade would work the best, since it would allow us to catch deprecations and handle the framework changes a bite at a time.

What I discovered in the end was that Rails itself uses so much “magic”, and directly modifies so many core Ruby API’s that it was impossible to predict what would break between versions. As an example, a minor version change from 1.2.3 to 1.2.4 caused unexpected changes in how dates were handled. The change-logs made no reference to such modifications. The change from 2.1 to 2.2 resulted in a host of modules no longer being identified. Oh sure, if you printed it out, Ruby “thought” it was available, but the minute you tried to actually use anything within the module, you would receive “uninitialized constant” errors on the module name itself.

I know everyone has their own opinions on the matter, but from where I stand using Ruby on Rails on a system even vaguely large and complex simply raises far too many question marks on predictability and a clean upgrade path.

As a comparison, let’s refer to Java 2 Enterprise. Every piece of code I have ever written in J2EE version 1.0 runs without any issue under a J2EE version 3 container. Not even a re-compile was required. I do realise that the comparison is somewhat unfair – but the point still remains. I have very rarely needed to make major changes to any Java-based application to cater for a new framework – especially between minor version numbers.

I hate to make a blanket case for all agile/dynamic frameworks, so I’ll admit that was probably unfair (Grails, Django are on my to-do list). However, my case is even held fast on a more superficial level – my own benchmarks on a variety of languages clearly show that although time and effort may be saved on initial development time, dynamic/typeless languages will always suffer in raw speed, and agile frameworks will always suffer from a degree of unpredictability when upgrading (this becomes immensely exaggerated when “auto-magic” comes into play, as there is no clear path when anything does break).

To be clear, I won’t abandon agile frameworks – if I just want a simple website up, and expect maybe a dozen hits a month, I’m certainly not going to do it in a full blown enterprise container – but in the same token, I would certainly not use any such framework in a banking environment!