Do not import duplicated modules with --importmode=importlib

[nicoddemus]

Regression brought up by #11475.

[nicoddemus]

@flying-sheep I could not reproduce the issue using your reproducer, in 7.4.4, 8.1.0 and this branch I get the same error:

======================================================= ERRORS ========================================================
________________________________ ERROR collecting scanpy/_utils/compute/is_constant.py ________________________________
ImportError while importing test module 'c:\Users\bruno\projects\scanpy\scanpy\_utils\compute\is_constant.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
scanpy\_utils\compute\is_constant.py:12: in <module>
    from ..._compat import DaskArray
.env\lib\site-packages\scanpy\__init__.py:19: in <module>
    from ._utils import check_versions
.env\lib\site-packages\scanpy\_utils\__init__.py:33: in <module>
    from .compute.is_constant import is_constant  # noqa: F401
E   ImportError: cannot import name 'is_constant' from 'scanpy._utils.compute.is_constant' (c:\Users\bruno\projects\scanpy\scanpy\_utils\compute\is_constant.py)

Perhaps this is due to me running Windows? Can you try this branch yourself perhaps?

[bluetech]

Regardless of whether it fixes @flying-sheep's issue, the change LGTM

[flying-sheep]

Ah, sorry, the reproducer didn’t do what I thought it did.

This one works. I’ll check if this PR fixes things:

git clone https://github.com/scverse/anndata.git -b src2
cd anndata
python -m venv .venv
.venv/bin/pip install .[test] pytest@https://github.com/pytest-dev/pytest/releases/download/8.1.0/pytest-8.1.0-py3-none-any.whl
.venv/bin/pytest anndata src/anndata/tests/test_awkward.py::test_view src/anndata/tests/test_backed_sparse.py::test_empty_backed_indexing

FAILED src/anndata/tests/test_awkward.py::test_view[obsm] - Failed: DID NOT WARN. No warnings of type (<class 'anndata._warnings.ImplicitModificationWarning'>,) were emitted.
FAILED src/anndata/tests/test_awkward.py::test_view[varm] - Failed: DID NOT WARN. No warnings of type (<class 'anndata._warnings.ImplicitModificationWarning'>,) were emitted.
ERROR src/anndata/tests/test_backed_sparse.py::test_empty_backed_indexing[zarr-empty_list] - ImportError: cannot import name 'write_zarr' from 'anndata._io.zarr' (/home/phil/Dev/Python/_reproducers/anndata/.venv/lib/python3.11/site-packages/zarr/__init__.py)
ERROR src/anndata/tests/test_backed_sparse.py::test_empty_backed_indexing[zarr-empty_bool_mask] - ImportError: cannot import name 'write_zarr' from 'anndata._io.zarr' (/home/phil/Dev/Python/_reproducers/anndata/.venv/lib/python3.11/site-packages/zarr/__init__.py)

[flying-sheep]

OK, I tried

git clone https://github.com/scverse/anndata.git -b src2
cd anndata
python -m venv .venv
.venv/bin/pip install .[test] 'pytest@git+https://github.com/nicoddemus/pytest.git@11475-duplicated-imports'
.venv/bin/pytest anndata src/anndata/tests/test_awkward.py::test_view src/anndata/tests/test_backed_sparse.py::test_empty_backed_indexing

and it worked!

/edit: running all tests via .venv/bin/pytest also worked, so this PR probably covers all cases.

🥳

[nicoddemus]

Awesome, thanks @flying-sheep!

[aaraney]

I think this may have introduced a different regression. Consider the following project structure with two packages under the ns namespace:

ns
└── python
    ├── bar
    │   ├── ns
    │   │   ├── bar
    │   │   └── test
    │   │       ├── __init__.py
    │   │       ├── bar.py
    │   │       └── test_bar.py
    │   └── pyproject.toml
    └── foo
        ├── ns
        │   ├── foo
        │   └── test
        │       ├── __init__.py
        │       ├── foo.py
        │       └── test_foo.py
        └── pyproject.toml

In pytest==8.0.2, python -m pytest --import-mode=importlib correctly runs the tests from the top level ns directory. In pytest==8.1.1, python -m pytest --import-mode=importlib -o "consider_namespace_packaes=true", results in the following error:

========================== test session starts ===========================
platform darwin -- Python 3.9.16, pytest-8.1.1, pluggy-1.4.0
rootdir: /home/user/pytest-12074
collected 0 items / 2 errors

================================= ERRORS =================================
____________ ERROR collecting python/bar/ns/test/test_bar.py _____________
ImportError while importing test module '/home/user/pytest-12074/python/bar/ns/test/test_bar.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
python/bar/ns/test/test_bar.py:1: in <module>
    from .bar import value
E   ModuleNotFoundError: No module named 'test.bar'
____________ ERROR collecting python/foo/ns/test/test_foo.py _____________
ImportError while importing test module '/home/user/pytest-12074/python/foo/ns/test/test_foo.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
python/foo/ns/test/test_foo.py:1: in <module>
    from .foo import value
E   ModuleNotFoundError: No module named 'test.foo'
======================== short test summary info =========================
ERROR python/bar/ns/test/test_bar.py
ERROR python/foo/ns/test/test_foo.py
!!!!!!!!!!!!!!!! Interrupted: 2 errors during collection !!!!!!!!!!!!!!!!!
=========================== 2 errors in 0.04s ============================

[aaraney]

Just a little bit of a follow up, because I realize that my original comment wasn't the most clear. Below are the contents of test_foo.py and foo.py. test_bar.py and bar.py look nearly identical.

# python/foo/ns/test/test_foo.py
from .foo import value

def test_foo():
    assert value == "foo"

# python/foo/ns/test/foo.py
value = "foo"

[nicoddemus]

@aaraney thanks for the report, but could you open a new issue please (you can refer to this one there)?

I will take a look at it ASAP. 👍

[aaraney]

@nicoddemus, for sure! Thanks for taking a look at this!