No output when stdin used on Windows

[PeterJCLaw]

If running type file.py | isort - --diff on Windows there is often no output given, even if there is sorting to do. This affects at least the VSCode integration and possibly other IDE integrations.

I actually think this is a Python bug (reported as https://bugs.python.org/issue40540), however there may be something which isort can do to work around it.

Currently isort looks for a coding comment in the input source and thus seeks within the input file having done that. Unfortunately that seems to cause issues on Windows, where further reads from stdin return no data.

For microsoft/vscode-python#9128 we're working around this by replacing stdin with an io.BytesIO so that isort can reliably seek within that stream. Obviously this isn't great and while it's not isort's fault (and this likely affects other tools too), one option would be for isort itself to use this io.BytesIO trick (or an equivalent fix) so that individual integrations don't need to patch around it.

I realise that the main focus of development now appears to be on 5.x, however would you be open to a patch against the 4.x stream which fixed this issue there?

[timothycrosley]

Thanks for reporting! This is verified to be fixed on the latest release.