ImportError: cannot import name 'Datasette' from partially initialized module 'datasette.app'

[simonw]

Got this with datasette-test>=0.3 as a dependency. I'm going to yank that release.

[simonw]

[simonw]

I clearly introduced a circular import when I made this a plugin in #4.

[simonw]

Traceback:

datasette-secrets % pytest
======================================================================= test session starts =======================================================================
platform darwin -- Python 3.10.10, pytest-8.1.1, pluggy-1.5.0
rootdir: /Users/simon/Dropbox/Development/datasette-secrets
configfile: pyproject.toml
plugins: anyio-4.3.0, asyncio-0.23.6
asyncio: mode=strict
collected 0 items / 1 error                                                                                                                                       

============================================================================= ERRORS ==============================================================================
_____________________________________________________________ ERROR collecting tests/test_secrets.py ______________________________________________________________
ImportError while importing test module '/Users/simon/Dropbox/Development/datasette-secrets/tests/test_secrets.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/opt/homebrew/Caskroom/miniconda/base/lib/python3.10/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/test_secrets.py:4: in <module>
    from datasette.cli import cli
../datasette/datasette/cli.py:17: in <module>
    from .app import (
../datasette/datasette/app.py:40: in <module>
    from .views.database import database_download, DatabaseView, TableCreateView
../datasette/datasette/views/database.py:35: in <module>
    from datasette.plugins import pm
../datasette/datasette/plugins.py:64: in <module>
    pm.load_setuptools_entrypoints("datasette")
/opt/homebrew/Caskroom/miniconda/base/lib/python3.10/importlib/metadata/__init__.py:171: in load
    module = import_module(match.group('module'))
/opt/homebrew/Caskroom/miniconda/base/lib/python3.10/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
../../../.local/share/virtualenvs/datasette-secrets-rV3AX-Bq/lib/python3.10/site-packages/datasette_test/__init__.py:1: in <module>
    from datasette.app import Datasette as _Datasette
E   ImportError: cannot import name 'Datasette' from partially initialized module 'datasette.app' (most likely due to a circular import) (/Users/simon/Dropbox/Development/datasette/datasette/app.py)
===================================================================== short test summary info =====================================================================
ERROR tests/test_secrets.py
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
======================================================================== 1 error in 0.29s =========================================================================

[simonw]

I'm pretty sure what's happening is that even attempting to import datasette_test.plugins is triggering an import of that datasette_test/__init__.py module which tries to import from datasette.app before it's ready.

[simonw]

I'm going to split it off into a separate plugin package, and make that a dependency of datasette-test.