Python Build Environment Variables Investigation

This skill helps you discover all environment variables that can be set when building Python wheels for a project. It performs a comprehensive analysis of build configuration files to identify customizable environment variables used during the wheel building process.

Instructions

When a user asks about environment variables for building Python wheels, investigating build configuration, or understanding build customization options:

1. Run the Environment Variables Investigation Script:

   ./scripts/env_finder.py [project_path]
   

2. Analyze and present the findings focusing on:

   Build Configuration Variables

   • Setup.py Variables: Environment variables used in setup.py for customizing builds
   • CMake Variables: Variables defined in CMakeLists.txt and related files
   • Build Tool Variables: Variables used by setuptools, distutils, or other build systems
   • Compiler Variables: Variables affecting compilation (CC, CXX, CFLAGS, etc.)

   Variable Categories

   Compiler and Linker Variables

   • CC, CXX - Compiler selection
   • CFLAGS, CXXFLAGS - Compilation flags
   • LDFLAGS - Linker flags
   • LIBS - Additional libraries

   Path Configuration Variables

   • PREFIX - Installation prefix
   • LIBRARY_PATH - Library search paths
   • INCLUDE_PATH - Header file paths
   • PKG_CONFIG_PATH - pkg-config search paths

   Feature Control Variables

   • ENABLE_* - Feature enable/disable flags
   • WITH_* - Optional component inclusion
   • USE_* - Build option selection
   • DISABLE_* - Feature disable flags

   Python-Specific Variables

   • PYTHON_INCLUDE_DIR - Python headers location
   • PYTHON_LIBRARY - Python library path
   • SETUPTOOLS_* - Setuptools configuration
   • PIP_* - pip-related build variables

   Usage Context

   • When Variables Are Used: During which build phase each variable takes effect
   • Default Values: What happens when variables are not set
   • Required vs Optional: Which variables are mandatory for successful builds

3. Provide actionable guidance:

   • How to set each variable for custom builds
   • Common use cases for each variable
   • Potential conflicts or compatibility issues
   • Recommended values for different scenarios

Output Format

The skill should provide a structured list of environment variables with:

1. Variable Name: Exact environment variable name
2. Purpose: Clear description of what the variable controls
3. Type: Expected value type (path, boolean, string, number)
4. Default Value: What happens when not set
5. Source File: Where the variable was discovered
6. Usage Context: When and how the variable is used

Error Handling and Edge Cases

No Build Configuration Found

• Report that no environment variables were found
• Most packages don't have build configuration so it is fine