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@ptone ptone commented Oct 15, 2025

Replace inefficient list comprehensions with for loops

Summary

This PR improves memory efficiency in the BirdFish lighting control framework by replacing list comprehensions used only for side effects with regular for loops. The codebase had 12 instances where list comprehensions were creating temporary list objects that were immediately discarded, consuming unnecessary memory and CPU cycles in performance-critical rendering code.

Changes:

  • birdfish/lights.py: Converted 9 list comprehensions to for loops in BaseLightElement.update(), BaseLightElement.trigger(), LightGroup.trigger(), LightGroup.set_intensity(), Chase.render(), and Spawner.spawn()
  • birdfish/effects.py: Converted 2 list comprehensions to for loops in Twinkle.update() and Twinkle._off_trigger()
  • birdfish/output/base.py: Converted 1 list comprehension to for loop in BaseNetwork.update_data()
  • Added efficiency_report.md documenting this and 5 other potential efficiency improvements

All changes are purely mechanical transformations from [expr for x in items] to for x in items: expr with no logic changes.

Review & Testing Checklist for Human

  • Run existing test suite - I couldn't run pytest in the environment, so runtime behavior is unverified
  • Test live lighting control - Verify the system still works correctly at 40 FPS with actual hardware/simulation
  • Spot check the transformations - Review a few of the changes to confirm they're semantically equivalent (e.g., lines 181-182, 355-358, 583-587 in lights.py)

Test Plan

  1. Run python -m pytest tests/ to verify existing tests pass
  2. If possible, test with actual lighting hardware or simulation to ensure rendering still works correctly
  3. Monitor memory usage to confirm the optimization has the expected positive impact

Notes

  • All 12 transformations follow the same pattern and should be safe, but untested changes in performance-critical code warrant careful review
  • The efficiency report identifies 5 additional optimization opportunities for future consideration
  • Session: https://app.devin.ai/sessions/e0ad765cdb26445bb7a1238dadd30d17
  • Requested by: Preston Holmes (@ptone)

Replace list comprehensions used only for side effects with regular for loops.
This eliminates unnecessary list object creation in performance-critical code paths.

Changes:
- lights.py: Converted 9 list comprehensions to for loops in trigger, update, render, and spawn methods
- effects.py: Converted 2 list comprehensions to for loops in Twinkle update method
- output/base.py: Converted 1 list comprehension to for loop in update_data method

These changes improve memory efficiency and reduce CPU overhead in the real-time
lighting control loop that runs at 40 FPS.

Co-Authored-By: Preston Holmes <preston@ptone.com>
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Summary of Changes

Hello @ptone, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request focuses on enhancing the performance of the BirdFish lighting control framework by addressing specific Python coding patterns that were creating unnecessary overhead. By converting list comprehensions used for side effects into more direct for loops, the changes aim to reduce temporary object creation, thereby conserving memory and CPU cycles in performance-critical rendering code. This is a foundational step towards a more optimized and responsive real-time lighting system.

Highlights

  • Performance Optimization: Replaced 12 instances of inefficient list comprehensions, used only for side effects, with standard for loops across birdfish/lights.py, birdfish/effects.py, and birdfish/output/base.py to improve memory and CPU efficiency.
  • Code Semantics: The transformations are purely mechanical, converting [expr for x in items] to for x in items: expr, ensuring no logic changes were introduced.
  • Documentation: A new file, efficiency_report.md, has been added to document this optimization and identify 5 additional potential efficiency improvements for future consideration within the BirdFish framework.
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Code Review

This pull request effectively improves memory efficiency by replacing list comprehensions used for side effects with standard for loops. The changes are applied consistently across multiple files and are a welcome optimization for this performance-sensitive application. The new efficiency_report.md is also a valuable addition for tracking and planning future work. I've found one critical pre-existing bug that was carried over in the refactoring in birdfish/effects.py which will cause a NameError and should be addressed.

Comment on lines +208 to +209
for t in targets:
t.set_intensity(0)

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critical

This loop iterates over targets, but targets is not defined in this method's scope. This will raise a NameError at runtime. Based on the if block above and the logic in BaseEffect.get_targets, it seems you intended to use self.targets instead.

This appears to be a pre-existing issue, but since this line is being modified, it's a good opportunity to fix it.

Suggested change
for t in targets:
t.set_intensity(0)
for t in self.targets:
t.set_intensity(0)

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