Code review is the systematic examination of computer source code to find mistakes. It aims to improve overall software quality by identifying errors missed during initial development. Effective code review processes include pairing programmers, using tools to manage code review workflows, and establishing guidelines for what reviewers should evaluate like requirements, readability, performance, and error handling. Selecting the right code review tool is important to support the chosen workflow and meet a team's particular needs.

1. How to start performing
useful code reviews
Raquel Pau (@raquelpau)
rpau@walkmod.com
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2. What is Code / Peer Review
Code review is systematic examination (sometimes referred
to as peer review) of computer source code. It is intended to
find mistakes overlooked in the initial development phase,
improving the overall quality of software.
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3. The origins..
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Formal Code Inspection (Fangan 1976)
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4. Pair programming
u Very effective code review, finds defects early.
u Great for sharing knowledge, mentoring.
u Requires two developers, co-located
u Transient discussion
u Personalities
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5. Tool-assisted Code Review
u Managed workflow and notification
u Record of discussion
u Asynchronous
u Change team culture?
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6. “Always code as if the person who ends
up maintaining your code is a violent
psychopath who knows where you live”
John F. Woods (1991)
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7. The human factor
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8. The team: introducing code review
u Communicate clearly
u Listen to concerns
u Cultivate code review culture
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9. Code Review benefits
u Finding bugs
u Spread code ownership
u Exchange knowledge and ideas
u Increased bus factor
u Promote and evolve standards across an organization
u Mentor developers
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10. Change impact
u Who?
u What?
u When?
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11. Process
u Decide the contribution workflow
u Patches / Branches / Pull requests
u Keep workflow simple
u Iterations are good
u Average 2 reviewers
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Work on feature/fix
Commit the change
Review the change
Done
Problems
found
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12. Tools
u Yes, you need a code review tool
u Find the right tool:
u Fits in your environment
u Supports chosen workflow
u Meets your particular needs
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13. As a code author
u Review your own code
u Commit small changes
u Document your code
u Provide meaningful commit messages
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14. As a reviewer
u Don’t postpone it (mental flows interruptions)
u Don’t spend too much time (10min, 30min, 1h)
u Keep in mind your project’s priorities
u Manage technical debt properly
u Apply your expertise
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15. Use Quality Gates & CI tools
u Tests execution
u Test Coverage
u Code Style Analysis
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16. What to look for? Create your own
checklist!
u Requirements correctness
u Readability
u Architecture and design
u Performance
u Errors & Security management
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17. Requirements correctness
u Are tests descriptive enough?
u Are there any bugs?
u Are the business rules and logic fully implemented and
tested?
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18. Readability
u Use appropriate names
u Documentation
u Define and use formatters
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19. Architecture and design review
u Are we modifying the same files over and over again?
u Is this functionality already implemented in another
place?
u Are there any libraries to perform that?
u Data structures
u Is this over engineered?
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20. Performance
u Performance requirements
u Performance tests
u Common causes of performance problems:
u Unnecessary network calls
u Using locks to access shared resources
u Potential memory leaks
u Not closed connections/streams
u Calls to databases 20
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21. Errors & security management
u Errors are handled properly
u Are using special codes/exceptions for each problems
u Authentication
u Third party libraries
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22. Human factor
u Ego-free reviews
u Do not be a pedant
u Find problems, not solutions
u Embrace feedback
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23. Workflow: validate as quick as possible
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Send a patch
to apply
Hook
Clone the project and
apply the patch
Receives the
patch to review
Build Project
Quality GateWrite code
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24. Workflow: validate as quick as possible
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Send a patch
to apply
Hook
Clone the project and
apply the patch
Receives the
patch to review
Build Project
Quality GateWrite code
#legacycoderocks

25. Pre code-review tools
u Test coverage
u Build problems
u Static code analysis tools
u Detect style issues
u Detect common bugs
u Detect dead code
u Detect design issues
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26. code-review tools
u Pull requests
u GitHub / Bitbucket
u Upsource
u Jetbrains
u FishEye + Crucible
u Atlassian (JIRA)
u Gerrit (open source)
u Google
u Reviewable.io
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27. code-review tools: pull-requests
u It is a diff / patch visualization
u A thread of comments
u Usually people express their opinions with +1, -1,
+1000 J
u After an agreement, project owners can apply the
patch
u The code review is merged
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28. code-review tools: upsource
u Integrated static code analysis
u Code navigation
u Find usages
u IDE plugin
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30. code-review tools: fisheye
u Great integration with Atlassian products
u Crucible, Bitbucket + JIRA
u Like Pull requests
u Share pieces of code
u Open discussions
u Validate patches /diffs.
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31. code-review tools: gerrit
u Gerrit manages the real changes to the final
repository.
u It becomes the developer repository:
git clone ssh://gerrithost:29418/RecipeBook.git
u Special branches for code review
git push origin HEAD:refs/for/master
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33. code-review tools: reviwable.io
u SaaS solution
u https://reviewable.io/
u Improved used experience from GitHub pull
requests.
u Shows you what changed since last time you looked
u Manages comments so your inbox does not overflow.
u Integrates effortless with GitHub pull requests
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34. thanks for your attention
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Raquel Pau (@raquelpau)
rpau@walkmod.com
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