Broken Windows Alexander Tamoykin http://alextamoykin.com 

Agenda •What •Why •How 

What is broken Windows? 

What What ? 

Lunch 

Changed your mind ? 

Just go with it 

William Bratton 

Simplified Code Example class SWE < ActiveRecord::Base! has_many :registrations! ! def go_to_conference! my_registration = registrations.find_by_swe_id id! my_registration.book! end! end 

How do we get there ? class SWE < ActiveRecord::Base! has_many :flights! has_many :registrations! ! def go_to_conference! my_flight = flights.find_by_swe_id id! my_flight.book! my_registration.book = registrations.find_by_swe_id id! my_registration.book! end! end 

Where do we stay ? class SWE < ActiveRecord::Base! has_many :flights! has_many :hotels! has_many :registrations! ! def go_to_conference! my_hotel = hotels.find_by_swe_id id! my_hotel.book! my_flight = flights.find_by_swe_id id! my_flight.book! my_registration = registrations.find_by_swe_id id! my_registration.book! end! end 

What if the conference is sold out ? class SWE < ActiveRecord::Base! has_many :flights! has_many :hotels! has_many :registrations! ! def go_to_conference! my_registration = registrations.find_by_swe_id id! ! if my_registration.book! my_hotel = hotels.find_by_swe_id id! my_hotel.book! my_flight = flights.find_by_swe_id id! my_flight.book! end! end! end 

What if there is no hotel ? class SWE < ActiveRecord::Base! has_many :flights! has_many :hotels! has_many :registrations! ! def go_to_conference! my_registration = registrations.find_by_swe_id id! if my_registration.book! my_hotel = hotels.find_by_swe_id id! if my_hotel.book! my_flight = flights.find_by_swe_id id! my_flight.book! end! end! end! end 

Hard to change! 

Is this easier to change ? class SWE < ActiveRecord::Base! …! def go_to_conference! register! book_hotel! book_flight! end! ! def book_flight! my_flight = flights.find_by_swe_id id! my_flight.book! end! ! def book_hotel! my_hotel = hotels.find_by_swe_id id! my_hotel.book! end! ! def register! my_registration = registrations.find_by_swe_id id! my_registration.book! end! end 

How did it happen ? class SWE < ActiveRecord::Base! has_many :flights! has_many :hotels! has_many :registrations! ! def go_to_conference! my_registration = registrations.find_by_swe_id id! if my_registration.book! my_hotel = hotels.find_by_swe_id id! if my_hotel.book! my_flight = flights.find_by_swe_id id! my_flight.book! end! end! end! end 

Human Nature • Survive • Adapt to the environment • Do what everyone else does 

What’s the problem ? Cost to Change Technical Debt 

What’s the problem ? Cost to Change Technical Debt 

Why • Legacy Code • Time Pressure • It can’t be worse 

Pragmatic Advise 

How • Identify a broken window • Refactor it • Track it • Come back and do it right • Leave a comment 

Do it! Before it’s too late 

Concrete Examples • Write a missing test • Split a large class into smaller classes • Look at Code Climate • Delete dead code • Review a pull request • Take a fresh look tomorrow • Encourage your coworker to fix it • Incrementally refactor 

Most Importantly 

The End http://alextamoykin.com