Interdiffs are a feature in Review Board that makes it easy to see what changes between two iterations of a diff, substantially cutting down the time needed for review, and improving accuracy.

They are, however, not perfect, and tricky to debug, due to the complexity going on behind the scenes.

This guide will attempt to help walk you through debugging the interdiff code.

How Interdiffs Work

Diff Generation

When it comes down to it, an interdiff is a diff view between two patched versions of a file.

When you view a standard diff, we:

1. Fetch the original source file from a repository.
2. Create a copy of the source file and patch it.
3. Generate a diff between the original source file and the patched copy.