Musketeering Makes Problems Intractable

Musketeering is lumping multiple difficult problems together to present a giant, intractable, disaster.

The name comes from the famous slogan: All for one, and one for all!  Each musketeer supports the group, and the group supports each musketeer.  When multiple problems form as one, they become impossible to defeat.

Most developers have faced a classic Three Musketeer problem with legacy code:

1. The code is full of bugs
2. Unit testing is nearly impossible
3. Touching anything can have unknown side effects

Each of these issues are fixable on their own, together they bring development to a halt.

Why can’t you fix the bugs?  Because testing is nearly impossible and everything you touch has side effects.

Why can’t you write tests?  Because the code is tightly coupled, which produces side effects.  Also, it is full of bugs so we don’t know what the correct functionality is.

Why can’t you reduce side effects?  Because the code is buggy and there are no tests.  If you can’t separate the concerns, you can’t make progress.