`isort` does not search for config when using `--filename`

[karthiknadig]

If you have files in this structure:

project
   |- sub-package
        |- pyproject.toml
        |- something.py       

say that pyproject.toml configures for profile black.

Then, this works (picks up the profile black):

C:\project> python -m isort C:\project\sub-package\something.py

but this does not:

C:\project> type C:\project\sub-package\something.py | python -m isort - --filename C:\project\sub-package\something.py

but this does (notice the CWD)

C:\project\sub-package> type C:\project\sub-package\something.py | python -m isort - --filename C:\project\sub-package\something.py

In VS Code extension for isort we are using the stdin way to perform sorting. This is need to support the organize import on save capability. I was able to simulate the same problem using type (on windows) and cat (on linux).

reference issue: microsoft/vscode-isort#138

[karthiknadig]

Related: #1940

[kaste]

This looks like introduced via 0973421
which looks like a very strange commit because it just removes a line and it is not obvious why this should be okay. The line was introduced like a hotfix here: c0ebbd0

So generally the workaround is to just use --settings_path but with a path not the absolute file name. (--filename is a config option just used for the stdin case and basically does a settings_path = dirname(filename). I do a possible PR here but wasted now an hateful hour or so to get poetry to install this package, let alone run the tests. Damn.

Because isort depends on pip (>=21.1.1) which doesn't match any versions, version solving failed.