Code Change Impact Analyzer

A Python package and CLI that predicts which Python modules are impacted when a file changes.

What it does

Given a changed file (for example auth/login.py), the analyzer:

1. Parses project files.
2. Detects function definitions.
3. Builds import and call dependency graphs.
4. Maps function usage across modules.
5. Shows impacted modules.

Why engineers use it

• Understand blast radius before merging changes.
• Speed up code reviews in large codebases.
• Decide where to add or run tests.

Installation

pip install code-change-impact-analyzer

For local development:

pip install -e .[dev]

CLI Usage

impact-analyzer --root . --changed auth/login.py

Options:

• --root: project root directory to analyze (default: current directory)
• --changed: changed file path relative to root (required)
• --json: print JSON output

Example Output

Editing: auth/login.py
Impacted modules:
- api/routes.py
- user/service.py
- tests/test_login.py

How it works

The tool performs static analysis over Python source files:

• Collects module imports (import x, from x import y)
• Collects function definitions per module
• Collects function calls per module
• Builds reverse dependency graph to find modules depending on the changed module
• Expands impact by function-level usage signals

Limitations

• Dynamic imports and metaprogramming are not fully resolved.
• Runtime dispatch and monkey patching are not modeled.
• Best for conventional Python codebases.