God Module

ID: god_module | Severity: High (default)

A "God Module" is a file that has grown too large and taken on too many responsibilities.

Why this is a smell

• Violates Single Responsibility Principle: The module does too many things.
• Merge Conflicts: Frequent changes by different developers lead to constant conflicts.
• Fragility: Changes in one part of the module might unexpectedly break another part.
• Hard to Test: Requires complex setup to test various unrelated functionalities.

Detection Criteria

archlint identifies God Modules based on:

• Fan-in: Number of other modules depending on it.
• Fan-out: Number of modules it depends on.
• Churn: Frequency of changes in git.
• Lines of Code: Total size of the file.

How to fix

1. Identify Responsibilities: List all different tasks the module performs.
2. Extract Modules: Break the file into smaller, focused modules.
3. Facade Pattern: If the module acts as a coordinator, keep only the coordination logic and delegate the work to sub-modules.

Configuration

rules:
  god_module:
    severity: high
    fan_in: 15
    fan_out: 15
    churn: 20

ESLint Rule

This detector is available as an ESLint rule for real-time feedback in your editor.

// eslint.config.js
export default [
  {
    rules: {
      '@archlinter/no-god-modules': 'warn',
    },
  },
];

See ESLint Integration for setup instructions.