Thursday, 14 April 2011

The waterfall mindset

Some developers are reluctant to delete code. If I understand their logic correctly, it goes something like this:

Writing code takes effort. Therefore, removing code means wasted effort.

This relies on two fallacies.

Firstly, it assumes that code is valuable in of itself. But code is a liability, not an asset. Removing code while maintaining functionality creates value because it improves agility without costing anything that stakeholders care about.

Secondly, it assumes that code/functionality is the only purpose of development. But agile practitioners use development as a way of gaining information. So even if a change is fully backed-out and never restored, the process of developing that change yielded an improved understanding of the solution space.

I realise that deconstructing fallacies is somewhat of a fallacy itself. Counterproductive practices are more likely to be driven by psychological factors than by logical errors. In this case, I think that a reluctance to delete code is motivated by an attitude I call the waterfall mindset.

Within the waterfall mindset, coding proceeds through a series of decisions that are never revisited once made. It's very similar to a sequential development process, except that the phases can be in the mind of a single developer. Like normal waterfall development, it relies on the supremely unlikely possibility of getting decisions right the first time:
  • Generating reports is too slow? Let's cache them on the webserver.
  • Cached files are out of date? Let's write a cron job to renew them every night.
  • The webserver is under unacceptable load during the regeneration process? Let's delegate to a separate report server.
  • Report generation fails silently when there are network problems? Let's develop a custom protocol with failure semantics so that the webserver knows when to re-send messages to the report server.
  • And so on...
Or perhaps the report generation process itself could be profiled and optimised, eliminating the need for a caching mechanism altogether.

When I discover developers (including myself) in the grip of waterfall coding, I'm reminded of the nursery rhyme about the woman who swallowed a fly. It didn't work out well for her either.

2 comments:

  1. Organizations need to be assured the individuals that manage their projects can integrate methods to achieve sustainability goals and still achieve project specific objectives. Project Managers need credentials that validate their proficiency with these specialized qualities. PMP Certified and scrum certified project managers can learn, apply, and validate mastery of sustainability based project methods to meet these demands.

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  2. Thanks for your comment, Kylie. Personally, I'm skeptical of the effectiveness of credentials in validating skills, though I certainly agree that coaching and ongoing education are important.

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