Code Review Guide

Things to do before you start reviewing the PR

• Make sure you are familiar with the packages the PR modifies.

• Make sure you have enough continuous time to review the PR, use 300 LOC per hour to estimate.

• Make sure you can follow the updates of the PR in the next few work days.

• Read the description of the PR, if it's not easy to understand, ask the coder to improve it.

• For a bug fix PR, if there is no test case, ask the coder to add tests.

• For a performance PR, if no benchmark result is provided, ask the coder to add a benchmark result.

Things to check during the review process

• Am I able to understand the purpose of each unit test?

• Do unit tests actually test that the code is performing the intended functionality?

• Do unit tests cover all the important code blocks and specially handled errors?

• Could procedure tests be rewritten to table driven tests?

• Is the code written following the style guide?

• Is the same code duplicated more than twice?

• Do comments exist and describe the intent of the code?

• Are hacks, workarounds and temporary fixes commented?

• Does this function do more than the name suggests?

• Can this function's behavior be inferred by its name?

• Do tests exist and are they comprehensive?

• Do unit tests cover all the important code branches?

• Could the test code be extracted into a table-driven test?

Things to keep in mind when you are writing a review comment

• Be kind to the coder, not to the code.

• Ask questions rather than make statements.

• Treat people who know less than you with respect, deference, and patience.

• Remember to praise when the code quality exceeds your expectation.

• It isn't necessarily wrong if the coder's solution is different than yours.

• Refer to the code style document when necessary.

Things to remember after you submitted the review comment

• Checkout Github notification regularly to keep track of the updates of the PR.

• When the PR has been updated, start another round of review or give it a LGTM.