The document discusses code smells and how to fight them. It describes various static code analysis tools like Reek, Flog, and Flay that can detect code smells without running the code. These tools can find issues like duplicated code, complex methods, long parameter lists, and more. The document also recommends using dynamic analysis tools in RubyMine that provide on-the-fly code inspection to catch problems. It emphasizes that there is no single cure for all code smells and developers should learn, get code reviews, use pair programming, and leverage both static and dynamic analysis tools.

1. 6/4/13
Fighting Code That
Smells
Anna Bulenkova
JetBrains Software Developer

2. What’s that smell?

3. WARNING
KEEP CHILDREN AWAY
FROM THIS CONTENT

8. Why?

9. Experience

10. Interruptions

11. Tiredness

12. Who cares...

13. Other Issues

14. What
happens?

15. • undefined local variable or method `call_me' for
main:Object (NameError)
warning: Object#id will be deprecated; use Object#object_id
• warning: Object#id will be deprecated; use
Object#object_id
• Dead code
• Copy/Paste
• Complexity
• code_styleAnd_FWpatternViolations

16. • undefined local variable or method `call_me' for
main:Object (NameError)
warning: Object#id will be deprecated; use Object#object_id
• warning: Object#id will be deprecated; use
Object#object_id
• Dead code
• Copy/Paste
• Complexity
• code_styleAnd_FWpatternViolations

17. • undefined local variable or method `call_me' for
main:Object (NameError)
warning: Object#id will be deprecated; use Object#object_id
• warning: Object#id will be deprecated; use
Object#object_id
• Dead code
• Copy/Paste
• Complexity
• code_styleAnd_FWpatternViolations

18. • undefined local variable or method `call_me' for
main:Object (NameError)
warning: Object#id will be deprecated; use Object#object_id
• warning: Object#id will be deprecated; use
Object#object_id
• Dead code
• Copy/Paste
• Complexity
• code_styleAnd_FWpatternViolations

19. • undefined local variable or method `call_me' for
main:Object (NameError)
warning: Object#id will be deprecated; use Object#object_id
• warning: Object#id will be deprecated; use
Object#object_id
• Dead code
• Copy/Paste
• Complexity
• code_styleAnd_FWpatternViolations

20. • undefined local variable or method `call_me' for
main:Object (NameError)
warning: Object#id will be deprecated; use Object#object_id
• warning: Object#id will be deprecated; use
Object#object_id
• Dead code
• Copy/Paste
• Complexity
• code_styleAnd_FWpatternViolations

21. How to fight?

22. • Learn
• Re-read
• Ask for review
• Pair programming
• Use tools

23. Code quality tools
•Static
•Runtime

24. • No code run
• But tool runs
• No side effects
• But no on-the-fly change
Static tools
false positeve
bad alalyzing meta-programming
false positeve
bad alalyzing meta-programming

25. Reek
• Control Couple
• Data Clump
• Feature Envy
• Large Class/Method
• Long Parameters List
• Simulated Polymorphism

26. Control Couple

27. Data Clump

28. Feature Envy

29. Large Class/Method
One
Third

30. Long Parameter List
QuickTime™ and a
H.264 decompressor
are needed to see this picture.

31. Simulated
Polymorphism
• instance_of?
• kind_of?
• is_a?
• ===
• Especially with case

32. Flog
• ABC Metric
• |ABC| = sqrt((A*A)+(B*B)+(C*C))

33. ABC Guide Lines0-10 = Awesome
•11-20 = Good enough
•21-40 = Might need refactoring
•41-60 = Possible to justify
•61-100 = Danger
•100-200 = Whoop, whoop, whoop
•200 + = Someone please think of the
children

34. ABC = 8.5

35. Flay
• Duplicates
• Ignores names / literals / values
• Ignores code style

36. Roodi• Assignment in conditionals
• Case missing else
• Line count
• Names check
• Cyclomatic omplexityс
• Empty rescue body
• For to foreach
• Parameters number
подровнятьподровнять

37. metrics_fu/metrical
• Flay
• Flog
• Rails Best Practices
• Reek
• Roodi
• Dynamic tools
• Fancy HTML report

38. Where to get?

39. Who’s gonna clean
everything for me?

40. RubyMine
• Inspections
• Duplicates

41. RubyMine Inspections
• Static
• On-the-fly analysis

43. Static analysis
QuickTime™ and a
H.264 decompressor
are needed to see this picture.

44. QuickTime™ and a
H.264 decompressor
are needed to see this picture.
On-The-Fly Analysis

45. Duplicates

46. There’s no cure-all

47. 6/4/13
Thanks for
watching!