Name: Learning A New Codebase? Here's How To Figure Out What Matters
Uploaded: 2022-04-09T18:37:55+00:00
Duration: 3 min 43 s
Description: Learn how to blame the code (i.e

Learning A New Codebase? Here's How To Figure Out What Matters

- Learn how to blame the code (i.e. know who wrote each line of code)
- A lot of people don't realize that when it comes to big companies, there are huge swaths of the codebase where nobody really knows how they work
- When absorbing the codebase on a new team/stack, go through the various classes/files in your ecosystem, and use blame to understand the hotspots, the code that's been changed frequently and recently by people. Don't just try to understand the entire codebase straight up.
  - Use the test plans of connected commits/code reviews to better understand how to run the code and what it does
  - Maintain the system: This is another reason why *you* should have great test plans on your diffs/commits, so you can keep your team's codebase well-documented and easy to learn

Code review is one of the most common and powerful ways for software engineers to learn. On top of increasing code quality, it builds engineering culture within a team.

Code review can catch coding mistakes and design flaws before the code reaches production

A good code review process is needed to catch bugs, increase maintainability, and guarantee a high velocity future contributors.

Code review ensures high quality software that is maintainable for the lifetime of the code

Tech has so much to learn, making learning how to learn one of the most important things for any software engineer to do. Figure out what you need to do to pick up new skills quickly and properly.

With how often software engineers change teams, it's crucial to be efficient at this. Learn how to get coding within a new codebase fast, build the proper relationships, and hit the ground running in general.

[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)