codex/prs/bolinfest/study/PR-3060-study.md

DOs

• Avoid unnecessary clones in comparisons: Compare borrowed values directly; cloning allocates needlessly.

  // Good
  let is_current = preset.model == current_model && preset.effort == current_effort;
  

• Log state changes with before/after context: Include both previous and new values to make audits useful.

  let prev_model = current_model.clone();
  let prev_effort = current_effort;
  let model_slug = preset.model.to_string();
  let effort = preset.effort;
  
  let actions: Vec<SelectionAction> = vec![Box::new(move |tx| {
      tx.send(AppEvent::UpdateModel(model_slug.clone()));
      tx.send(AppEvent::UpdateReasoningEffort(effort));
      tracing::info!(
          "Model change: prev={}, new={}; Effort: prev={}, new={}",
          prev_model, model_slug, prev_effort, effort
      );
  })];
  

• Clone only at ownership boundaries: Clone when an API requires owned data; borrow for formatting/logging.

  tx.send(AppEvent::UpdateModel(model_slug.clone())); // needs owned String
  tracing::info!("New model: {}", model_slug);        // borrow; no clone
  

• Use concise, consistent log phrasing: Keep keys stable and values inline for grepability.

  tracing::info!("Model change: prev={}, new={}; Effort: prev={}, new={}", prev_model, model_slug, prev_effort, effort);
  

DON'Ts

• Don’t clone just to compare: Cloning for equality checks wastes CPU and allocates.

  // Bad
  let is_current = preset.model == current_model.clone() && preset.effort == current_effort;
  

• Don’t clone just to log: tracing/format! take references; cloning adds no value.

  // Bad
  tracing::info!("New model: {}", model_slug.clone());
  

• Don’t shadow when capturing previous state: Use a distinct name instead of reusing the same identifier.

  // Bad
  let current_model = current_model.clone();
  
  // Good
  let prev_model = current_model.clone();
  

• Don’t log only the new value: Without the previous value, change events are hard to interpret.

  // Bad
  tracing::info!("New model: {}", model_slug);
  
  // Better
  tracing::info!("Model change: prev={}, new={}", prev_model, model_slug);