check-duplicate-functions 1.0.0

A Python tool to detect duplicate function names in Python source files using AST parsing

check-duplicate-functions

A Python tool to detect duplicate function names in Python source files using AST (Abstract Syntax Tree) parsing.

Repository: https://github.com/pandiyarajk/check-duplicate-python-functions

Author: Pandiyaraj Karuppasamy ([e-mail])

Features

• Detects duplicate function names: Identifies functions with the same name defined multiple times in a file
• AST-based analysis: Uses Python's built-in AST module for accurate parsing
• Handles async functions: Properly identifies and distinguishes async functions
• Class context awareness: Tracks function context (module-level vs class methods)
• Special method exclusion: Excludes special methods (like __init__, __str__, etc.) from duplicate checks since they can legitimately appear in multiple classes
• Signature extraction: Extracts and compares function signatures including type annotations
• Comprehensive error handling: Handles file not found, permission errors, encoding issues, and syntax errors gracefully

Requirements

• Python 3.6 or higher
• No external dependencies (uses only Python standard library)

Installation

Option 1: Install from PyPI (Recommended)

pip install check-duplicate-functions

After installation, you can use the command-line tool:

check-duplicate-functions <python_file_path>

Option 2: Clone the repository

git clone https://github.com/pandiyarajk/check-duplicate-python-functions.git
cd check-duplicate-python-functions
python check_duplicate_functions.py <python_file_path>

Option 3: Download directly

No installation required. Simply download the check_duplicate_functions.py file and run it:

python check_duplicate_functions.py <python_file_path>

Usage

If installed from PyPI:

check-duplicate-functions <python_file_path>

If using the script directly:

python check_duplicate_functions.py <python_file_path>

Examples

# Check a single Python file (PyPI installation)
check-duplicate-functions my_script.py

# Check a file in a subdirectory (PyPI installation)
check-duplicate-functions src/utils.py

# Using the script directly
python check_duplicate_functions.py my_script.py
python check_duplicate_functions.py src/utils.py

Output

The script produces output only when duplicates are found or errors occur:

• No duplicates: Script exits silently with exit code 0
• Duplicates found: Prints each duplicate function name and the line numbers where it appears:

  [DUPLICATE] 'my_function' appears on lines: 10, 25, 42
  

• Errors: Prints error messages for file not found, syntax errors, etc.:

  [ERROR] File not found: nonexistent.py
  [ERROR] Syntax error in file.py: invalid syntax (line 5)
  

Exit Codes

• 0: Success (no duplicates found or analysis completed successfully)
• 1: Error (invalid arguments, file not found, syntax error, or other issues)

How It Works

1. File Reading: Reads the Python source file with UTF-8 encoding
2. AST Parsing: Parses the source code into an Abstract Syntax Tree
3. Function Extraction: Traverses the AST to extract all function definitions:
   • Regular functions (def)
   • Async functions (async def)
   • Methods within classes
   • Function signatures with type annotations
4. Duplicate Detection: Identifies functions with duplicate names (excluding special methods)
5. Result Reporting: Prints duplicate function names and their line numbers

Special Methods

Special methods (dunder methods) like __init__, __str__, __repr__, etc. are excluded from duplicate checking because:

• They are expected to appear in multiple classes
• They serve specific purposes in Python's object model
• Having them in multiple classes is not considered a code quality issue

Limitations

• Only analyzes a single file at a time (no recursive directory scanning)
• Does not detect duplicates across different files
• Special methods are excluded from duplicate detection
• Functions with identical names but different signatures are still reported as duplicates

Error Handling

The script handles various error conditions:

• File not found: Returns appropriate error message
• Permission denied: Reports permission errors
• Encoding errors: Handles files with non-UTF-8 encoding issues
• Syntax errors: Reports Python syntax errors with line information
• Unexpected errors: Catches and reports any unexpected exceptions

Example Use Cases

• Code review: Quickly identify potential duplicate function definitions before code review
• Refactoring: Find duplicate functions that might need to be consolidated
• Code quality: Maintain clean codebase by detecting accidental function name reuse
• Large codebases: Analyze individual files in large projects for duplicate functions

License

This project is provided as-is for use in detecting duplicate functions in Python code.

Contributing

Contributions are welcome! Please feel free to submit issues or pull requests on GitHub.

Author

Pandiyaraj Karuppasamy

• Email: [e-mail]
• GitHub: @pandiyarajk