Project Meeting 2025.05.22

Agenda

• Dependency lock update

Technical

• What is a dependency lock
  • A practice of freezing the versions of all dependencies used in the project
  • Make sure all dependencies are updated and always work together
• Current issues in ActivitySim that would be solved with dependency lock
  • Unexpected issues due to updates in dependencies
  • Unstable and non-reproducible environments
  • Unsuccessful installations accross different platforms
• There are many python project manager options to consider
  • Pip
    • Used by default in python
    • Super slow
    • pip freeze - hacky way of doing your best to lock dependencies
  • Conda
    • handles languages beyond Python
    • Currently what ActivitySim most relies on
    • Conda lock - third party package
    • Slow
  • PDM (Python Development Master)
    • Installs package from PyPI
    • Fast
    • good lock file
  • UV
    • Really fast
    • Replacement of Pip
    • Sophisticated lock file
  • Pixi
    • Similar to Conda
    • Fast
    • Has its own lock file
  • Poetry
    • Has its own lock file
    • Slow
• Recent publication of Dependency Lock Standard (PEP 751)
  • pylock.toml - tool-agnostic standard for lock files
• Speed is important for picking a tool
• Recommend testing three options
  • Pip, PDM, UV
  • Test includes user experience, creating ActivitySim virtual environment, creating and updating lock file, installing from lock file into a new virtual environment, run example models w/ and w/o Sharrow, supportin GitHub Actions, publishing to index
• Please send feedback to consider throughout testing
• Will provide update in early June