A CLI tool that parses git diffs and provides intelligent, contextual explanations of code changes. Identifies programming language, summarizes changes, flags potential issues, and suggests improvements - all running locally without external API dependencies.

Features

Parse git diffs/patches: Extract file names, hunks, and code changes from unified diff format
Identify programming language: Detect language from file extensions and code patterns
Summarize changes: Generate human-readable summaries of what each change does
Flag potential issues: Detect bugs, security vulnerabilities, and code smells
Suggest improvements: Provide specific refactoring suggestions
Local execution: Runs entirely offline using local libraries
Color-coded output: Terminal output with ANSI colors for better readability

Installation

# Using pip
pip install git-diff-explainer-cli

# From source
git clone <repository>
cd git-diff-explainer-cli
pip install -e .

Usage

Basic Usage

# Explain a diff from stdin
git diff | gdiffer explain --stdin

# Explain a diff file
gdiffer explain --file changes.diff

# Pass diff as argument
gdiffer explain "diff --git a/file.py b/file.py..."

# Get just the summary
gdiffer summarize --file changes.diff

# Check for issues only
gdiffer issues --file changes.diff

Options

# Output format: terminal (default), json, plain
gdiffer explain --output json

# Verbose output
gdiffer explain --verbose

Examples

Simple Diff Explanation

$ git diff | gdiffer explain
=== Git Diff Analysis Summary ===
Total files changed: 1
Files added: 0
Files deleted: 0
Files modified: 1
Total changes: 3

Languages:
  - python: 1 files

=== File Changes ===

1. src/main.py
   Status: modify
   Changes: 3 lines
   Hunk 1:
    +import os
    +import sys
    def main():
        print("Hello, World!")

JSON Output

$ gdiffer explain --output json "diff --git a/test.py..."
{
  "summary": {
    "total_files": 1,
    "files_added": 0,
    "files_deleted": 0,
    "files_modified": 1,
    "total_changes": 2
  },
  "files": [...]
}

Issue Detection

$ gdiffer issues --file sql_injection.diff
[CRITICAL] Potential SQL Injection
  File: db.py:5
  Description: String concatenation or interpolation used in SQL query
  Suggestion: Use parameterized queries or ORM methods

Supported Languages

Python
JavaScript / TypeScript
Java
Go
Rust
C / C++
Ruby
PHP
And more...

Configuration

Environment variables:

Variable	Description	Default
`GDIFF_OUTPUT`	Output format: terminal, json, plain	terminal
`GDIFF_VERBOSE`	Enable verbose output	false

Development

# Install development dependencies
pip install -e ".[dev]"

# Run tests
pytest tests/ -v

# Run with coverage
pytest tests/ --cov=src/gdiffer

# Type checking
mypy src/gdiffer/

# Linting
ruff check src/gdiffer/

Error Handling

Common errors and solutions:

Error	Solution
Invalid git diff format	Provide a valid unified diff format
No changes detected	Ensure the diff contains actual code changes
Unsupported language	Use a supported language or file extension

License

MIT

Description

Readme MIT 179 KiB