How do I understand a large GitHub PR quickly?

To understand a large GitHub pull request quickly, work out what it does before you read any code. Find the features it ships, follow the most important one end to end, and check what it touches. DiffGuardian does the first and third of those for you and speeds up the second. It works with pull requests on GitHub, GitLab and Bitbucket.

#A fast way in, without any tool

1. Read the title, description and linked issue. Know what it claims to do.
2. Open the file list, not the diff. Group the files by area to see how many separate changes there are.
3. Pick the riskiest change and read it first, from where it starts to where it ends.
4. Skim the mechanical changes once you have confirmed they are mechanical.
5. Check callers of anything that changed shape.

#With DiffGuardian

1. Connect your repository and open the pull request. The change is split into the features it ships, each explained in plain English.
2. Read it: Trace It (Pro) walks a feature across every file it touches.
3. Hear it: Talk to your pull request (Pro) gives you the walkthrough out loud while the code is highlighted.
4. See it: the blast radius graph shows what the change reaches, built from the diff alone.

The short version is in the docs: Understand a pull request quickly.

DiffGuardian is a desktop app for macOS, Windows and Linux.

#Limits

• It needs an AI provider for the walkthrough: a local model, or your own key for a cloud provider.
• Trace It and voice are Pro features. The blast radius graph needs no AI and works on every plan.
• It never merges anything. You approve when you are ready.