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Software Engineering · Quality

Code Review

Reference entry · last updated 20260908

Code review is the examination of proposed source changes to assess their design, behavior, clarity, and fit with a codebase. Google’s guidance includes checking functionality, complexity, tests, naming, comments, and documentation.[1]

First principles and definitions

A reviewer compares the change with its intended behavior and surrounding system. A pull request is one place to conduct that review. Tests supply evidence for the cases they cover; review can also question whether the intended change is appropriate.

Review scope

• Check what the change is meant to accomplish and whether the design fits the system.
• Read the changed behavior and its tests, including failure paths.
• Check whether names, comments, and documentation make the change understandable.

These checks summarize Google’s reviewer guidance.[1] Small, focused changes reduce the amount of context a reviewer must hold at once.[2]

Limits of approval

Approval records a review decision. It does not establish that all defects have been found. Automated reviewers also need their findings checked against the actual code and requirements.

Queueing theory offers a model for waiting work, but review counts alone do not measure the depth of review.

See also

• Acceleration Whiplash
• Pull Requests
• Software Quality Assurance
• Adversarial Review (AI Agents)

References

1. Google Engineering Practices. What to look for in a code review.
2. Google Engineering Practices. Small CLs.