It is inevitable that at some point in your career as a developer you will inherit code developed by others. Trying to understand code developed by someone else can often lead to stress and frustration, but it doesn't have to. This talk will provide you with tools and techniques to help understand and begin working with code from other developers quickly and easily.

1. Inheriting Code
Anthony Eden
Tuesday, June 8, 2010

2. Who are you?
Tuesday, June 8, 2010

3. Explorer
Tuesday, June 8, 2010
You’ll need to be willing to travel down uncharted paths and create a map to find your way
out.

4. Historian
Tuesday, June 8, 2010
You’ll need to understand what got the code here.

5. Forensic Analyst
Tuesday, June 8, 2010
You’ll need to understand the motives by looking at the crime scene.

6. Psychic
Tuesday, June 8, 2010
You’ll need to read minds.

7. Sadist
Tuesday, June 8, 2010
You’ll need to be able to hurt the code.

8. Masochist
Tuesday, June 8, 2010
You’ll need to be able to withstand the pain that the code causes you.

9. Prepare
Tuesday, June 8, 2010
Adjust your mode of thinking.

10. Assume
nothing
Tuesday, June 8, 2010

11. You are not smarter,
just different
Tuesday, June 8, 2010
Put yourself in the mind of the author.
Keep an open mind about implementations that are different from how you might do it.
Understand why they may have written code in the way they did.

12. Learn
Tuesday, June 8, 2010

13. Read
Tuesday, June 8, 2010
Read the code
Read the documentation

14. Cause and Effect
Tuesday, June 8, 2010
What were the business needs that caused this code to be written?
What other factors were present when the code was written?

15. Find the dragons
Tuesday, June 8, 2010
What code was written to solve an immediate problem, but never refactored?
What code was written to old APIs?
What code was written in different styles by different developers?

16. Act
Tuesday, June 8, 2010

17. Resolve Dependencies
Tuesday, June 8, 2010

18. Run the test suite
Tuesday, June 8, 2010

19. Write tests where
there are none
Tuesday, June 8, 2010
Top down approach with Cucumber.
Bottom up approach with RSpec, Shoulda or plain Test::Unit.
If tests are already written then start
Regardless you’ll need both.

20. Simplify complex code
Tuesday, June 8, 2010
When a test is written you can refactor it.

21. Reduce
Tuesday, June 8, 2010
Reduce the amount of code.
Remove unused methods and classes.
Version control is your friend.

22. Have a rollback strategy
Tuesday, June 8, 2010
You will misunderstand the purpose of some of the code.
Be able to rollback easily.
Version control is essential.
Make small changes.

23. Make small
changes
Tuesday, June 8, 2010
Small changes are easier to fix.
Small changes are easier to undo.

24. Compartmentalize
Tuesday, June 8, 2010
Break down monolithic code into smaller chunks.
Break down large features into smaller ones.

25. Protect
the
data
Tuesday, June 8, 2010
Along with code you’ll be inheriting data.

26. Write for maintainability
Tuesday, June 8, 2010
New features are always tested.

27. Follow conventions
Tuesday, June 8, 2010
Rails conventions are your friend.

28. Deploy Early,
Deploy Often
Tuesday, June 8, 2010

29. Build a
better
legacy
Tuesday, June 8, 2010

30. Share knowledge
Tuesday, June 8, 2010
Pairing helps tremendously here
Perform code reviews

31. http://www.flickr.com/photos/natedreger/4272271989/
http://www.flickr.com/photos/atelier_tee/212176187/
http://www.flickr.com/photos/h-k-d/3617751660/
http://www.flickr.com/photos/vogelium/2623770180/
http://www.flickr.com/photos/9619972@N08/2636808004/
http://www.flickr.com/photos/emeraldrose/3587025487/
http://www.flickr.com/photos/mcgraths/3248483447/
http://www.flickr.com/photos/inhalingsounds/4444522392/
http://www.flickr.com/photos/rossinabossio/289756071/
http://www.flickr.com/photos/wili/2628869994/
http://www.flickr.com/photos/fofurasfelinas/2549402702/
http://www.flickr.com/photos/ironrodart/4154904299/
http://www.flickr.com/photos/myrmician/228790898/
http://www.flickr.com/photos/29487767@N02/3644730871/
http://www.flickr.com/photos/teacherafael/2038442136/
http://www.flickr.com/photos/gamene/4015192611/
http://www.flickr.com/photos/shewatchedthesky/2835193235/
http://www.flickr.com/photos/myreflex/180524429/
http://www.flickr.com/photos/tzofia/202684786/
http://www.flickr.com/photos/capedcrusader/3713232485/
http://www.flickr.com/photos/jaxxon/93296381/
http://www.flickr.com/photos/jbird/19650368/
http://www.flickr.com/photos/joeharper/3872936498/
http://www.flickr.com/photos/bassclarinetist/4448830860/
http://www.flickr.com/photos/winterofdiscontent/3301816514/
http://www.flickr.com/photos/74274915@N00/3554610230/
http://www.flickr.com/photos/tal_axl/4297212753/
http://www.flickr.com/photos/essjay/2397379457/
Tuesday, June 8, 2010