Name: Avoid These Junior Engineer Mistakes With Code Review
Uploaded: 2022-04-14T04:51:38+00:00
Duration: 3 min 40 s
Description: In this video segment, we reflect on common mistakes and best practices around code submissions, especially relevant to

Avoid These Junior Engineer Mistakes With Code Review

In this video segment, we reflect on common mistakes and best practices around code submissions, especially relevant to early-career engineers. The discussion centers around how to be thoughtful and intentional in code reviews to earn trust and increase velocity over time.

- **We don’t treat code review as a speed game.** Moving fast at the cost of quality—like deferring fixes or separating tests from the initial diff—often backfires. We strive to bundle fully thought-out changes with tests as one atomic, reviewable unit.
- **We use RFC diffs to gather early feedback.** When we're unsure of direction, we create “Request for Comment” diffs clearly labeled as such. This helps reviewers give high-level input without getting stuck on minor details.
- **We always show proof of testing, even for small changes.** Even if our change is minimal (e.g., a refactor or doc update), we still confirm it compiles and passes existing tests to signal due diligence.
- **We think like reviewers.** Providing context, test signals, and clarity up front not only earns trust but speeds up the feedback loop and helps us land code more efficiently.

In this video segment, we reflect on common mistakes and best practices around code submissions, especially relevant to 

[Masterclass] How To Do Amazing Code Review

Code review is one of the most effective ways to learn as a software engineer, especially for those earlier-in-career. Unfortunately, way too many engineering teams get it wrong with slow review speed and low quality comments.

There is a mountain of information in this presentation, so here's our 5 favorite points (in no particular order):
- **Code review is NOT for catching bugs** - Of course, if you find a bug in a PR (pull request), you should call it out, but that's not the primary purpose of code review. The core benefit of code review is to build up engineering culture, propagating best practices amongst the team and growing newer and more junior engineers.
- **Add deep context to your PRs** - Explain what your pull request does and the reasoning behind your approach. Also, *include a test plan.* A test plan is a demo showcasing what your code changes do; try to make it a video/gif, which is especially powerful if you work on front-end (Android/iOS/web). If you can't do a video, try attaching a screenshot or a set of commands to run tests.
- **One diff, one thesis** - Every PR should be focused and atomic: Don't jam the entire new feature you just coded up in a single 1,000+ line PR. Huge commits are hard to review, and your teammates will hate you for it. For the vast majority of cases, you can break down your PRs to 25-250 lines of code.
- **Read others' code reviews** - Similar to so many other things in tech, stand on the shoulders of giants where you can. With code review, this means looking at how senior+ engineers on your team comment on reviews. Try to find patterns in the issues they're finding and incorporate it into how you review code. Revisions that have been rejected with changes requested are a gold mine for this learning.
- **Code review MUST be fast** - When we say fast, we mean that feedback should arrive in <24 hours. What a lot of engineers don't realize is that code review delay is multiplicative: Sometimes commit will need 3-5 revisions before they're able to be merged. If turnaround is 2+ days, this can easily lead to commits taking weeks to land, which is far too slow.

A lot of the terminology in this video is Meta specific. If you're more used to GitHub:
- Diff review = Pull request
- Diff = Commit

Related resources:
- ["How to give better code reviews without full business context?"](https://www.jointaro.com/question/vio35mw1SYWM8AYojB2w/how-to-give-better-code-reviews-without-full-business-context/)
- ["How to review code in another language/ from another team?"](https://www.jointaro.com/question/B79W3aWc8xMB8cCULFdJ/how-to-review-code-in-another-language-from-another-team/)
- [Presentation Slides](https://docs.google.com/presentation/d/1koyIR9K_CtESD7Vnh3GQOE-svFW-ngrQeEAduSAoH0w/edit)