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assignment-to-os-environ (B003)#

Derived from the flake8-bugbear linter.

What it does#

Checks for assignments to os.environ.

Why is this bad?#

In Python, os.environ is a mapping that represents the environment of the current process.

However, reassigning to os.environ does not clear the environment. Instead, it merely updates the os.environ for the current process. This can lead to unexpected behavior, especially when running the program in a subprocess.

Instead, use os.environ.clear() to clear the environment, or use the env argument of subprocess.Popen to pass a custom environment to a subprocess.


import os

os.environ = {"foo": "bar"}

Use instead:

import os

os.environ["foo"] = "bar"