Name: The Most Common Mistake Made When Authoring Code Reviews
Uploaded: 2022-04-09T18:32:32+00:00
Duration: 4 min 18 s
Description: In this video, we focus on the critical importance of providing context when submitting code for review

The Most Common Mistake Made When Authoring Code Reviews

In this video, we focus on the **critical importance of providing context** when submitting code for review. As codebases grow in size and complexity, understanding the "why" behind a change becomes just as important as the code itself. Without clear context, reviewers are left in the dark—and teams lose valuable time and trust.

### Key Takeaways:

- **We explain the “why” behind every diff**: When submitting code, we clarify *why* the change exists, *why* we chose this approach, and *why* alternatives were rejected. This empowers reviewers to assess our choices without second-guessing or chasing us for clarification.
- **We include business, technical, and historical context**: Good diffs often explain the strategic purpose, relevant architecture, past experiments, and legacy code decisions—all of which help reviewers understand how our change fits into the larger system.
- **We reduce friction with thoughtful summaries**: A well-written diff summary is low-effort but high-impact. Taking 5–10 minutes to write it may feel like a tax, but it dramatically speeds up reviews and earns the gratitude of teammates.
- **We acknowledge that no one sees the whole system**: Using the “elephant” metaphor, we recognize that everyone sees only part of the codebase. Providing our view helps others see how our changes fit into the broader system, making collaboration more effective.
- **We write for humans, not just machines**: Code may be infinitely flexible, but humans need context to interpret it. By empathizing with reviewers and anticipating their questions, we make code review a faster, smoother, and more collaborative process.

In this video, we focus on the critical importance of providing context when submitting code for review

[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)