## Change Summary

This means `pydantic/__init__.py` is now lazy about all imports using `__getattr__`.

Import performance changes:
### Before

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 29.7 msec per loop
```

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"
1 loop, best of 1: 30.4 msec per loop
```

### After

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 4.8 msec per loop
```

```
(env3112) code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"           
1 loop, best of 1: 18.7 msec per loop
```

Tuna output:

<img width="1421" alt="image" src="https://github.com/pydantic/pydantic/assets/4039449/0a57434e-fdda-4709-8793-d96c0a0ee762">

## Related issue number

As promised in https://github.com/pydantic/pydantic/pull/7423#issuecomment-1733361629.

## Checklist

* [x] The pull request title is a good summary of the changes - it will be used in the changelog
* [ ] Unit tests for the changes exist
* [x] Tests pass on CI
* [ ] Documentation reflects the changes where applicable
* [x] My PR is ready to review, **please add a comment including the phrase "please review" to assign reviewers**


Selected Reviewer: @sydney-runkle
Use `__getattr__` for all package imports, improve import time. ## Change Summary

This means `pydantic/__init__.py` is now lazy about all imports using `__getattr__`.

Import performance changes:
### Before

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 29.7 msec per loop
```

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"
1 loop, best of 1: 30.4 msec per loop
```

### After

```
code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "import pydantic"
1 loop, best of 1: 4.8 msec per loop
```

```
(env3112) code/pydantic 0 ➤ pdm run python -m timeit -n 1 -r 1 "from pydantic import BaseModel"           
1 loop, best of 1: 18.7 msec per loop
```

Tuna output:

<img width="1421" alt="image" src="https://github.com/pydantic/pydantic/assets/4039449/0a57434e-fdda-4709-8793-d96c0a0ee762">

## Related issue number

As promised in https://github.com/pydantic/pydantic/pull/7423#issuecomment-1733361629.

## Checklist

* [x] The pull request title is a good summary of the changes - it will be used in the changelog
* [ ] Unit tests for the changes exist
* [x] Tests pass on CI
* [ ] Documentation reflects the changes where applicable
* [x] My PR is ready to review, **please add a comment including the phrase "please review" to assign reviewers**


Selected Reviewer: @sydney-runkle
name: Upload Previews

on:
  workflow_run:
    workflows: [CI]
    types: [completed]

permissions:
  statuses: write

jobs:
  upload-previews:
    if: ${{ github.event.workflow_run.conclusion == 'success' }}
    runs-on: ubuntu-latest

    steps:
      - uses: actions/setup-python@v4
        with:
          python-version: '3.10'

      - run: pip install smokeshow

      - uses: dawidd6/action-download-artifact@v2
        with:
          workflow: ci.yml
          commit: ${{ github.event.workflow_run.head_sha }}

      - run: smokeshow upload coverage-html
        env:
          SMOKESHOW_GITHUB_STATUS_DESCRIPTION: Coverage {coverage-percentage}
          # 5 is set here while V2 is in development and coverage is far from complete
          SMOKESHOW_GITHUB_COVERAGE_THRESHOLD: 91
          SMOKESHOW_GITHUB_CONTEXT: coverage
          SMOKESHOW_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          SMOKESHOW_GITHUB_PR_HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
          SMOKESHOW_AUTH_KEY: ${{ secrets.SMOKESHOW_AUTH_KEY }}

name: Upload Previews

on:
  workflow_run:
    workflows: [CI]
    types: [completed]

permissions:
  statuses: write

jobs:
  upload-previews:
    if: ${{ github.event.workflow_run.conclusion == 'success' }}
    runs-on: ubuntu-latest

    steps:
      - uses: actions/setup-python@v4
        with:
          python-version: '3.10'

      - run: pip install smokeshow

      - uses: dawidd6/action-download-artifact@v2
        with:
          workflow: ci.yml
          commit: ${{ github.event.workflow_run.head_sha }}

      - run: smokeshow upload coverage-html
        env:
          SMOKESHOW_GITHUB_STATUS_DESCRIPTION: Coverage {coverage-percentage}
          # 5 is set here while V2 is in development and coverage is far from complete
          SMOKESHOW_GITHUB_COVERAGE_THRESHOLD: 91
          SMOKESHOW_GITHUB_CONTEXT: coverage
          SMOKESHOW_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          SMOKESHOW_GITHUB_PR_HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
          SMOKESHOW_AUTH_KEY: ${{ secrets.SMOKESHOW_AUTH_KEY }}
