Go beyond the usual practices

1. Super
charging
project
health
check
go beyond the usual
practices
David
Horvath
Lead iOS Developer
@egyes
Swifters meetup
2021 March

2. digital
agency
┘ Lot of different projects throughout the years
┘ Project handovers
┘ Code audits

3. issues
┘ Tons of things to check
┘ Lot of different approaches
┘ Require a lot of time (it’s never enough)
┘ Huge projects - Potentially overlooked problems

4. goals
┘ Find the most crucial issues in the shortest time
┘ Be more efficient in gaining insights
┘ Efficiently identify the changes to the code which provide the most value

5. useful
when
┘ You have to do a project audit
┘ You join a new project
┘ You just want to get new insights into your current project
┘ You want to refactor or rewrite
∷ You can show these findings to your client/boss/lead

6. process
┘ Checking git reports
∷ Interesting details about the project
∷ Gitlab / Github - GitStats(SourceForge)

7. git reports

8. process
┘ Checking git reports
∷ Interesting details about the project
∷ Gitlab / Github - GitStats
┘ Checking project size

9. cloc

10. process
┘ Checking git reports
∷ Interesting details about the project
∷ Gitlab / Github - GitStats
┘ Checking project size
∷ Cloc
┘ Open the project and build it
∷ High-level overview

11. high-
level
overview
┘ File structure
┘ Naming conventions
┘ Modularization
┘ Dependencies (spm, pod, carthage)
┘ UI (code / xib / storyboards)
┘ Architecture
┘ Compile time
┘ Xcode memory graph

12. process
┘ Checking git reports
∷ Interesting details about the project
∷ Gitlab / Github - GitStats
┘ Checking project size
∷ Cloc
┘ Open the project and build it
∷ Highlevel overview
┘ Visualize class dependencies

13. dependency visualizer

14. dependency visualizer

15. process
┘ Checking git reports
∷ Interesting details about the project
∷ Gitlab / Github - GitStats
┘ Checking project size
∷ Cloc
┘ Open the project and build it
∷ Highlevel overview
┘ Visualize class dependencies
∷ objc-dependency-visualizer
┘ Static code analysis
∷ Cyclomatic complexity
∷ Code duplication

16. lizard

17. lizard

18. process
┘ Checking git reports
∷ Interesting details about the project
∷ Gitlab / Github - GitStats
┘ Checking project size
∷ Cloc
┘ Visualize class dependencies
∷ objc-dependency-visualizer
┘ Checking cyclomatic complexity
∷ Lizard
┘ Static code analysis
∷ Cyclomatic complexity
∷ Code duplication
∷ Lizard / CPD
┘ Checking dead code

19. periphery

20. process
┘ Checking git reports
∷ Interesting details about the project
∷ Gitlab / Github - GitStats
┘ Checking project size
∷ Cloc
┘ Visualize class dependencies
∷ objc-dependency-visualizer
┘ Checking cyclomatic complexity
∷ Lizard
┘ Static code analysis
∷ Cyclomatic complexity
∷ Code duplication
∷ Lizard / CPD
┘ Checking dead code
∷ Periphery

21. quick
process
summary
┘ We have a lot of information about the project already
∷ High-level overview
∷ Data about the project size and age
∷ List of complexities
∷ List of duplication
∷ Duplication rate
∷ List of unused codes
∷ Nice visualization of the class dependencies
┘ It only took a few hours

22. so
what’s
new?

23. problems
┘ We spend so much time looking at the current state of the code
that we forget its history
┘ Its hard to understand large-scale complex systems by looking
at a snapshot of the code
┘ We miss a lot of information

24. where can
we find
more info?

25. version
control
systems
┘ We use it to keep track of the project history
┘ Rarely think about the insights we can get by mining data from it
┘ We can learn about the environment
┘ We can learn about how we work
┘ Predict which parts of the code have the most defects
┘ Find the code that matters most for maintenance
┘ Information is real power

26. git log

27. code
maat
┘ Command line tool
┘ To mine and analyze data from version control systems
┘ It supports different version control systems
∷ git, svn, perforce, tfs, mercurial
┘ We can use it to detect hotspots
┘ We can use it to detect architectural problems
┘ And so much more

28. generate maat readable log

29. summary

30. Hotspots
┘ Hotspots are your guide to improvements and
refactorings
┘ Research has shown that frequent changes to complex
code generally indicate declining quality
┘ Over time our development focus shifts so the hotspots
will also shift
┘ Hotspots can predict defects very well
┘ We can find them at the intersection of complexity and
effort

31. revisions (changes)

32. cloc --by-file

33. cloc --by-file

34. merge them for hotspots

37. Coupling
┘ We can detect which files are changing together most
of the time
┘ Detect architectural / design issues
┘ Explicit coupling
∷ What tend to change together (screen + vm)
┘ Temporal coupling
∷ This is what we are looking for
∷ Can be false positives (service + test)
∷ Can be serious design problem
∷ Can be copy-paste

38. sum of coupling

39. coupling by files

40. false positives

41. true problems

42. path transformation

43. transformed coupling info

44. transformed coupling info

45. other
features
┘ Complexity trends
∷ Evaluate growth patterns
∷ Analyze complexity trends
┘ Discover organizational metrics
∷ Social problems
∷ Evaluate communication costs
∷ Build knowledge map
∷ Visualize knowledge loss
┘ Code chur
∷ Predict defects
∷ Discover process loss from code

46. process
summary
┘ High-level overview of the codebase
┘ List of complexities
┘ List of duplications
┘ List of unused codes
┘ List of hotspots
┘ List of problematic dependencies

47. goals
┘ ✅ Find the most crucial issues in the shortest time
┘ ✅ Be more efficient in gaining insights
┘ ✅ Efficiently identify the changes to the code which provide the most
value

48. suggesti
ons
┘ Run these analyses every few months
┘ Can be part of CI/CD release process
┘ Talk the findings through with your team
┘ Read Adam Tornhill’s book to learn more:
Your Code as a Crime Scene

49. sum up
┘ With the right tools you can quickly and efficiently spot
problems
┘ You can use your version control systems to have more
information about your project
┘ By mining data from it, you can get a deeper
understanding of your design / architectural problems
┘ With the right data you can back your refactoring/
rewrite proposals
┘ Focusing on the right things early you can save a lot of
maintenance cost

50. thank
you
for your
attention
David
Horvath
Lead iOS Developer
@egyes

51. tools
┘ GitStats
∷ http://gitstats.sourceforge.net
┘ Cloc
∷ https://github.com/AlDanial/cloc
┘ Lizard
∷ https://github.com/terryyin/lizard
┘ Periphery
∷ https://github.com/peripheryapp/periphery
┘ Objc-dependency-visualizer
∷ https://github.com/PaulTaykalo/objc-dependency-visualizer
┘ Swift-dependency-visualizer
∷ https://github.com/PrzemyslawCholewaDev/swift-dependency-
visualizer
┘ Code maat
∷ https://github.com/adamtornhill/code-maat