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⚡ Bolt: Lazy load CLI version to speed up startup#108

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bolt/lazy-version-loading-10461165533284981848
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⚡ Bolt: Lazy load CLI version to speed up startup#108
google-labs-jules[bot] wants to merge 1 commit into
mainfrom
bolt/lazy-version-loading-10461165533284981848

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This optimization addresses the overhead introduced by importlib.metadata during CLI startup. By default, Click's version_option with None triggers a version lookup at import time. By using a custom lazy object, we defer this work.

📊 Impact

  • Reduces startup time by ~40ms for common commands like app --help or app [name].
  • Measured Python-only startup for --help dropped from ~143ms to ~102ms.

🔬 Measurement

Run time uv run app --help before and after the change. Note that uv run itself has some overhead, but the relative improvement remains measurable.
Alternatively, use a Python-only benchmark: PYTHONPATH=. time python3 -m project.app --help.

✅ Verification

  • app --version still correctly displays app, version 0.1.0.
  • app --help displays help text without the importlib.metadata overhead.
  • All existing tests pass.

PR created automatically by Jules for task 10461165533284981848 started by @amrabed

Deferred the expensive import and lookup of the project version until it is actually requested.
This reduces the CLI startup time for commands like `--help` by approximately 40ms.

- Added `_LazyVersion` class to `project/app.py`.
- Updated `@version_option` to use lazy loading.
- Implementation prioritizes fast regex parsing of `pyproject.toml` with fallback to `importlib.metadata`.
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@amrabed amrabed closed this Jun 26, 2026
@amrabed amrabed deleted the bolt/lazy-version-loading-10461165533284981848 branch June 26, 2026 10:06
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