1 © Nokia 2015 Code review Adam Badura Public

2 © Nokia 2015 “systematic examination of computer source code” Public What is code review? Code review

3 © Nokia 2015 Code review is having other people look at your code in order to find defects. Public What is code review? Code review

4 © Nokia 2015 Pros & cons of code review Introducing code review to the team Measuring code review Best practices for good code review Public Agenda Code review

5 © Nokia 2015  prevents releasing bugs  ensures architecture quality  leads to personal development  takes time  is boring  hurts feelings Public Pros & cons of code review Code review

6 © Nokia 2015  ? prevents releasing bugs  ensures architecture quality  leads to personal development  takes time  is impractical when reviewer doesn’t know domain  hurts feelings Public Pros & cons of code review Code review

7 © Nokia 2015  prevents releasing bugs  ensures architecture quality  leads to personal development  takes time  is impractical when reviewer doesn’t know domain  hurts feelings Public Pros & cons of code review Code review

8 © Nokia 2015  prevents releasing bugs  ensures architecture quality  leads to personal development  ? takes time  is impractical when reviewer doesn’t know domain  hurts feelings Public Pros & cons of code review Code review

9 © Nokia 2015  prevents releasing bugs  ensures architecture quality  leads to personal development  takes time  is impractical when reviewer doesn’t know domain  hurts feelings Public Pros & cons of code review Code review

10 © Nokia 2015 Follow example or order Show that it works to give example Mind time taken when estimating Public Introducing code review to the team Code review

11 © Nokia 2015 Follow example or order Show that it works to give example Mind time taken when estimating Public Introducing code review to the team Code review

12 © Nokia 2015 Follow example or order Show that it works to give example Mind time taken when estimating Public Introducing code review to the team Code review

13 © Nokia 2015 Code review costs Code review isn’t a sellable product So how do we know that it is worth it? Because we measure it’s impact! Public Measuring code review Code review

14 © Nokia 2015 Code review costs Code review isn’t a sellable product So how do we know that it is worth it? Because we measure it’s impact! Public Measuring code review Code review

15 © Nokia 2015 Code review costs Code review isn’t a sellable product So how do we know that it is worth it? Because we measure it’s impact! Public Measuring code review Code review

16 © Nokia 2015 Code review costs Code review isn’t a sellable product So how do we know that it is worth it? Because we measure it’s impact! Public Measuring code review Code review

17 © Nokia 2015 External metrics Decrease in reported bugs Decrease in bugs traced to development Increase of defects detected Internal metrics Defects count Time spent Ratios including also reviewed code size Types of defects Public Measuring code review Code review

18 © Nokia 2015 External metrics Reported bugs Bugs traced to development Defects detected and prevented Internal metrics Defects count Time spent Ratios including also reviewed code size Types of defects Public Measuring code review Code review

19 © Nokia 2015 External metrics Reported bugs Bugs traced to development Defects detected and prevented Internal metrics Defects count Time spent Ratios including also reviewed code size Types of defects Public Measuring code review Code review

20 © Nokia 2015 External metrics Reported bugs Bugs traced to development Defects detected and prevented Internal metrics Defects count Time spent Ratios including also reviewed code size Types of defects Public Measuring code review Code review

21 © Nokia 2015 External metrics Reported bugs Bugs traced to development Defects detected and prevented Internal metrics Defects count Time spent Ratios including also reviewed code size Types of defects Public Measuring code review Code review

22 © Nokia 2015 External metrics Reported bugs Bugs traced to development Defects detected and prevented Internal metrics Defects count Time spent Ratios including also reviewed code size Types of defects Public Measuring code review Code review

23 © Nokia 2015 Ensure that you can objectively measure effects of code review Without that you don’t know whether it helps Also you don’t know if you should change it And if change it then how Public Measuring code review Code review

24 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

25 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

26 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

27 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

28 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate employees based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

29 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

30 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

31 © Nokia 2015 Limit size ( LOC) and time (1-2 hours) Iterate – check how corrections were applied Use supporting techniques. For example: Checklists Change description Don’t evaluate based on code review Mind your language Count the time! Tools help in the process rather than define it Public Best practices for good code review Code review

32 © Nokia Barkeep 2.cahoots 3.CodeReviewHub 4.CodeReviewer 5.Codebrag 6.Codifferous 7.Collaborator 8.Crucible 9.Differential 10.exercism 11.Gerrit 12.Gitcolony 13.GitHub Code Review 14.Kallithea 15.Malevich 16.Redmine + Code Review Plugin 17.Review Board 18.Reviewable 19.Reviewlead 20.Rietveld 21.TeamReview 22.Upsource Public Tools list Code review

33 © Nokia Best Kept Secrets of Peer Code Review 2.A Guide to Code Inspections 3.What Types of Defects Are Really Discovered in Code Reviews? 4.11 Best Practices for Peer Code Review 5.Wikipedia, “Code review” 6.Wikipedia, “Software inspection”  Quora, StackOverflow, …  Actual work Public References Code review

34 © Nokia 2015 ? Public Questions Code review