A presentation at PHPCon PL 2019 in in Szczyrk, Poland by Paweł Lewtak
Why choose legacy? Paweł Lewtak @pawel_lewtak
Code without tests Michael Feathers
Nobody sets out to write legacy code Rachel Willmer
Legacy != your enemy
If you look at your code written half a year ago and you wouldn’t change a thing, it means you didn’t learn in last half a year.
Butterfly Effect
No tests
No documentation
Your code = your responsibility
Rewrite or refactor?
Start from scratch
Refactoring
Plan
We’re programmers. Programmers are, in their hearts, architects, and the first thing they want to do when they get to a site is to bulldoze the place flat and build something grand. Joel Spolsky
When we refactor, we should have tests. To put tests in place, we often have to refactor. Michael Feathers
Pareto Rule
Mikado Method
Strangler pattern
The journey of a thousand miles begins with a single step Confucius
Remember, code is your house, and you have to live in it. Michael Feathers
Recommended books
Thank you
Most people would rather work on a greenfield project than a legacy one. On one hand, you have the freedom to choose a new language/framework/library to use and have fun learning that. On the other hand, there’s an existing project, maybe old one, that skipped a few updates of libraries, maybe not using latest features your language of choice gives you.
I’ll share my experience and show you why I like working with legacy projects, what’s interesting in them for me, how I improve as a developer working with them. Hopefully, that’ll allow you to enjoy working with legacy a bit more and hate it a bit less next time.
Here’s what was said about this presentation on social media.
for free. You
can too.