Configure Language-Aware Diff Drivers

Language-Aware Diff Drivers

Git has built-in support for language-specific diff drivers that improve the readability of git diff output. Instead of generic context lines, the diff hunk headers show the function, method, or class that contains the change.

Configuration

# Language-specific diffs
*.py    text diff=python
*.java  text diff=java
*.kt    text diff=kotlin
*.go    text diff=golang
*.rs    text diff=rust
*.rb    text diff=ruby
*.php   text diff=php
*.c     text diff=cpp
*.cpp   text diff=cpp
*.h     text diff=cpp
*.cs    text diff=csharp
*.html  text diff=html
*.css   text diff=css
*.md    text diff=markdown

Before and After

Without diff=python:

@@ -42,7 +42,7 @@
     return result

With diff=python:

@@ -42,7 +42,7 @@ def calculate_total(items):
     return result

The function name calculate_total(items) appears in the hunk header, making it immediately clear which function was modified.

Supported Languages

Git includes built-in word-regex patterns for these languages:

Driver	File types
python	.py, .pyx
java	.java, .gradle
kotlin	.kt, .kts
golang	.go
rust	.rs
ruby	.rb, .rake
php	.php
cpp	.c, .cpp, .h, .hpp
csharp	.cs
html	.html, .htm
css	.css, .scss
markdown	.md

Custom Diff Drivers

You can define custom drivers in .gitconfig:

[diff "swift"]
  xfuncname = "^[ \t]*(class|struct|enum|protocol|func|extension)[ \t].*$"

Then reference it in .gitattributes:

*.swift text diff=swift