gh-101754: Document that Windows converts keys in os.environ to upp…

…ercase (GH-101840) (cherry picked from commit 4e7c0cb) Co-authored-by: Owain Davies <[email protected]>
python · Mar 3, 2023 · 32a738e · 32a738e
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commit 32a738e
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
@@ -201,6 +201,11 @@ process and user.
    ``'surrogateescape'`` error handler. Use :data:`environb` if you would like
    to use a different encoding.
 
+   On Windows, the keys are converted to uppercase. This also applies when
+   getting, setting, or deleting an item. For example,
+   ``environ['monty'] = 'python'`` maps the key ``'MONTY'`` to the value
+   ``'python'``.
+
    .. note::
 
       Calling :func:`putenv` directly does not change :data:`os.environ`, so it's better