feat(virtualenv): add default environment support for pixi, conda, and mamba

[wyuenho]

Summary

• Adds pixi, conda, and mamba to virtualenv resolution order (steps 3-4)
• Pixi: extracts default environment from pixi info --json output
• Conda/Mamba: reads prefix directly from environment*.yml configuration files
• Updates virtualenv resolution documentation to reflect new order
• Adds comprehensive tests verifying each tool's virtualenv resolution

🤖 Generated with Claude Code

[claude]

Claude finished @wyuenho's task —— View job

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Code Review Complete ✅

• Read project guidelines from CLAUDE.md
• Analyze pet.el implementation changes
• Review test coverage and quality
• Evaluate code quality and best practices
• Check for potential bugs and issues
• Assess performance considerations
• Review security concerns
• Provide comprehensive feedback

Summary

This is a well-implemented feature that adds support for pixi, conda, and mamba to the virtualenv resolution order. The changes are clean, follow existing patterns, and include comprehensive test coverage.

✅ Strengths

Code Quality & Best Practices

• Excellent consistency: The implementation follows existing code patterns perfectly, using the same helper functions (pet-use-*-p, pet-run-process-get-output, let-alist) and coding style as the rest of the codebase
• Proper integration: New functionality integrates seamlessly into the existing virtualenv resolution order without disrupting existing behavior
• Clean separation of concerns: Each tool has its own detection logic while sharing common infrastructure

Implementation Details

• Pixi support (pet.el:1051-1057): Correctly extracts the default environment prefix from pixi info --json output using proper JSON parsing and alist navigation
• Conda/Mamba support (pet.el:1058-1061): Elegantly handles both tools by using the existing pet-environment function that reads environment*.yml files
• Documentation updates (pet.el:1040-1044): The docstring accurately reflects the new resolution order

Test Coverage

• Comprehensive coverage: All three new tools have dedicated test cases that verify the virtualenv resolution logic
• Proper mocking: Tests correctly mock dependencies and follow project conventions (no unnecessary let-binds, proper spy usage)
• Cache validation: Each test verifies that the resolved virtualenv is properly cached

🔍 Minor Observations

Potential Edge Cases

1. Pixi environment selection: The implementation assumes the "default" environment exists. Consider what happens if pixi info --json returns environments_info but no "default" key
2. Error handling: Both pixi and conda/mamba integrations rely on the underlying functions (pet-run-process-get-output, pet-environment) for error handling, which appears appropriate but could be documented

Code Organization

• Resolution order logic: The new tools are properly placed early in the resolution order (steps 3-4), which makes sense as they're project-specific package managers
• Function placement: The pixi logic is more complex than conda/mamba but still readable and maintainable

🚀 Performance Considerations

• Lazy evaluation: Good use of when-let* ensures expensive operations (process calls, JSON parsing) only happen when the tool is actually available
• Process calls: Both pixi and conda/mamba detection involve subprocess calls, but this is unavoidable and follows the existing pattern used by other tools
• Caching: The implementation properly leverages the existing cache system to avoid repeated expensive operations

🔒 Security Considerations

• Process execution: Uses existing secure process execution helpers (pet-run-process-get-output)
• JSON parsing: Uses the safe pet-parse-json function for handling pixi output
• File access: Follows existing patterns for configuration file access

📋 Test Quality Assessment

The tests follow project guidelines perfectly:

• ✅ No unnecessary let-binds
• ✅ Direct function calls in expect statements
• ✅ Proper spy mocking without explicit :and-return-value nil
• ✅ No obvious/useless comments
• ✅ Tests cover both success cases and proper cache integration

🎯 Overall Assessment

This is a high-quality implementation that:

• Follows established code patterns and conventions
• Provides comprehensive test coverage
• Integrates cleanly without breaking existing functionality
• Has proper documentation updates
• Uses appropriate error handling and security practices

The code is ready for merge. The implementation demonstrates good understanding of the codebase architecture and maintains the high quality standards of the project.

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