html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/5841#issuecomment-985473412,https://api.github.com/repos/pydata/xarray/issues/5841,985473412,IC_kwDOAMm_X846vSGE,9155111,2021-12-03T12:17:51Z,2021-12-03T12:33:59Z,CONTRIBUTOR,"See also #5236 which could be related which uses `conda`.

I tried to scour through pip and pytest issues, but I can't find a discussion on this. `pip` and `pytest` and `pycache`are too generic keywords. I even found [pytest plugin to remove bytecode but it does not work ~~anymore~~ for me](https://pypi.org/project/pytest-remove-stale-bytecode/).

I proposed a fix in #6039, which I believe is good to have, as you can't expect every user to execute with `python -B` or set `PYTHONDONTWRITEBYTECODE` while running tests.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1019478260
https://github.com/pydata/xarray/issues/5841#issuecomment-985386101,https://api.github.com/repos/pydata/xarray/issues/5841,985386101,IC_kwDOAMm_X846u8x1,9155111,2021-12-03T10:02:51Z,2021-12-03T10:02:51Z,CONTRIBUTOR,"This in my opinion is a cascade of multiple issues:
- `pytest` creates special bytecode
- `pip` does not clean the whole `__pycache__` directory on uninstall
- `xarray.pycompat.is_duck_dask_array` uses `importlib.import_module('dask')` to determine if it is installed.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1019478260
https://github.com/pydata/xarray/issues/5841#issuecomment-985379668,https://api.github.com/repos/pydata/xarray/issues/5841,985379668,IC_kwDOAMm_X846u7NU,9155111,2021-12-03T09:53:46Z,2021-12-03T09:53:46Z,CONTRIBUTOR,"@twhughes @keewis In my case, I encounter this when I:
- Have xarray + dask installed in my environment
- Run any pytest which imports xarray (which in turn imports dask)
- Uninstall dask, but pytest artefacts remain:

```sh
❯ ls venv/lib/python3.9/site-packages/dask/__pycache__
utils_test.cpython-39-pytest-6.2.5.pyc
```

Here are the steps which would *hopefully* reproduce the behaviour:

```py
# Create this small unit test named:
# test_import_xarray.py                                                     
def test_xr():
    import xarray
```

```sh
python -m venv venv
source venv/bin/activate
pip install xarray pytest dask
pytest test_import_xarray.py

pip uninstall dask
ls venv/lib/python3.9/site-packages/dask/__pycache__  # See output above
python -c 'import dask'  # No ImportError!
python -c 'import xarray'
```

Exact versions used Python 3.9.9 along with:
```sh
# requirements.txt
attrs==21.2.0
cloudpickle==2.0.0
dask==2021.11.2
fsspec==2021.11.1
iniconfig==1.1.1
locket==0.2.1
numpy==1.21.4
packaging==21.3
pandas==1.3.4
partd==1.2.0
pluggy==1.0.0
py==1.11.0
pyparsing==3.0.6
pytest==6.2.5
python-dateutil==2.8.2
pytz==2021.3
PyYAML==6.0
six==1.16.0
toml==0.10.2
toolz==0.11.2
xarray==0.20.1
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1019478260