Refactoring, Architecture, and Yagni

Refactoring has profoundly changed how people think about software architecture.

🌳 Old Mindset

• Software design & architecture should be worked on and mostly completed before writing code.

• Once code is written, its architecture is fixed and can only decay due to carelessness.

🌱 New Mindset: Evolutionary Architecture

• Refactoring allows us to significantly alter the architecture of software that's been running in production for years.

• Finishing Architecture before coding assumes the requirements for the software can be understood early on. Experience shows that this is usually an unachievable goal.

• People only understand what is needed from software once they have a chance to use it.

• As our understanding of user needs changes, we use refactoring to adapt the architecture to those new demands rather than speculate on what might be needed upfront.

• YAGNI: Simple, incremental design

  • Doesn't mean architectural thinking disappears or we neglect upfront thinking.

  • Preparatory thinking can still be valuable and save time.

• The balance has shifted to dealing with issues later when we understand them better.

  • See Also: Lean Software Development - Decide as late as possible