Re: BUG: git bash / python interaction with absolute paths as environment variables in Windows

From: Eric Sunshine <sunshine@sunshineco.com>
Date: Dec 7, 2021, 03:15 UTC
Message-ID: <CAPig+cQSEUguKRfCBLoDfLvH5orAX-_KZ+pZE=h4u2x3N_yNzQ@mail.gmail.com>
In-Reply-To: <CAHeq4YxktibxMBnMLwEq9Nvsgw0UqCrjW2WPcerJCM4mXKxiEw@mail.gmail.com>

On Mon, Dec 6, 2021 at 10:01 PM Leland Weathers <leland@lcweathers.net> wrote:

Show 19 quoted lines

> Issue: Using Git Bash for Windows (2.34.1-64) and Python 3.9.9, a git
> path is incorrectly prepended to environment variables in Python code.
>
> $ echo $TEST_DIR_BROKEN
> /foo/bar
> $ echo $TEST_DIR_WORKING
> foo/bar
> $ python foobar.py
> environ: C:/Users/Leland/AppData/Local/Programs/Git/foo/bar
> environ: foo/bar
>
> Is there anything else I'm missing on why the same Python script would
> read environment variables differently than what is read from Git Bash
> itself or why the exact same Python code reads the environment
> variable correctly when run from a command prompt and not in Git Bash?
>
> In both cases I am using the same Python virtual environment. Other
> environment variables (e.g. non-absolute directory paths) appear to be
> read correctly. I'm assuming that this is a git issue given the

This is probably not specific to Git, but rather a "feature" of MSYS2, which Git for Windows happens to employ for its Bash shell. When invoking Windows commands from within MSYS2, command-line arguments and environment variables on the Unix side which appear to be paths will be converted to Windows paths for the sake of the native Windows program (since it won't know anything about the Unix paths coming out of the MSYS2 environment).

This behavior is documented at [1]; in particular, see the "Environment Variables" section.

[1]: https://www.msys2.org/docs/filesystem-paths/