[pyflakes] Revert to stable behavior if imports for module lie in alternate branches for F401

[dylwil3]

Closes #20839

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

ℹ️ ecosystem check detected linter changes. (+0 -22 violations, +0 -0 fixes in 6 projects; 49 projects unchanged)

RasaHQ/rasa (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

- rasa/utils/plotting.py:35:20: F401 `tkinter` imported but unused; consider using `importlib.util.find_spec` to test for availability

apache/airflow (+0 -7 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview --select ALL

- devel-common/src/tests_common/pytest_plugin.py:2164:16: F401 `airflow.sdk._shared.logging` imported but unused; consider using `importlib.util.find_spec` to test for availability
- devel-common/src/tests_common/pytest_plugin.py:2167:20: F401 `airflow.sdk._shared.logging` imported but unused; consider using `importlib.util.find_spec` to test for availability
- providers/celery/src/airflow/providers/celery/executors/celery_executor_utils.py:120:16: F401 [*] `airflow.jobs.local_task_job_runner` imported but unused
- providers/celery/src/airflow/providers/celery/executors/celery_executor_utils.py:121:16: F401 [*] `airflow.macros` imported but unused
- providers/celery/src/airflow/providers/celery/executors/celery_executor_utils.py:124:16: F401 `airflow.providers.standard.operators.bash` imported but unused; consider using `importlib.util.find_spec` to test for availability
- providers/celery/src/airflow/providers/celery/executors/celery_executor_utils.py:125:16: F401 `airflow.providers.standard.operators.python` imported but unused; consider using `importlib.util.find_spec` to test for availability
- providers/celery/src/airflow/providers/celery/executors/celery_executor_utils.py:127:16: F401 [*] `airflow.operators.bash` imported but unused

binary-husky/gpt_academic (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

- crazy_functions/Multi_Agent_Legacy.py:57:16: F401 [*] `autogen` imported but unused

mlflow/mlflow (+0 -10 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

- tests/utils/test_model_utils.py:74:20: F401 [*] `dummy_module` imported but unused
- tests/utils/test_requirements_utils.py:320:16: F401 [*] `databricks` imported but unused
- tests/utils/test_requirements_utils.py:321:16: F401 [*] `databricks.automl` imported but unused
- tests/utils/test_requirements_utils.py:322:16: F401 [*] `databricks.automl_foo` imported but unused
- tests/utils/test_requirements_utils.py:323:16: F401 [*] `databricks.automl_runtime` imported but unused
- tests/utils/test_requirements_utils.py:324:16: F401 [*] `databricks.model_monitoring` imported but unused
- tests/utils/test_requirements_utils.py:332:16: F401 [*] `databricks.automl` imported but unused
- tests/utils/test_requirements_utils.py:333:16: F401 [*] `databricks.automl_foo` imported but unused
- tests/utils/test_requirements_utils.py:334:16: F401 [*] `databricks.automl_runtime` imported but unused
- tests/utils/test_requirements_utils.py:335:16: F401 [*] `databricks.model_monitoring` imported but unused

scikit-build/scikit-build (+0 -2 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

- skbuild/utils/__init__.py:33:12: F401 `setuptools.logging` imported but unused; consider using `importlib.util.find_spec` to test for availability
- tests/__init__.py:9:12: F401 `distutils` imported but unused

mesonbuild/meson-python (+0 -1 violations, +0 -0 fixes)

ruff check --no-cache --exit-zero --ignore RUF9 --no-fix --output-format concise --preview

- tests/test_editable.py:281:24: F401 [*] `pure` imported but unused

Changes by rule (1 rules affected)

code	total	+ violation	- violation	+ fix	- fix
F401	22	0	22	0	0

[dylwil3]

The ecosystem hits look correct - these two are debatable, but keeping the stable behavior seems fine for now:

• providers/google/src/airflow/providers/google/common/utils/id_token_credentials.py:43:12:
• mlflow/pyfunc/loaders/init.py:1:8:

[MichaReiser]

The examples with if TYPE_CHECKING are a bit unfortunate. Do you think it would be possible to instead test if the import is in an alternate branch than the other import?

E.g. the following should be flagged

if True:
	import a.b
	if other:
		import a.b

but not

if True:
	import a.b
else:
	if other:
		import a.b

So, I guess, we'd have to check if the first import ancestor chain is a prefix of the second import's ancestor chain

[MichaReiser]

Did this new approach improve the ecosystem results?

[dylwil3]

Did this new approach improve the ecosystem results?

Yes! The things that remain are variations on the try/except pattern in the original issue.