[3.13] gh-141570: can_colorize: Expect fileno() to raise OSError, as documented (#141716) (#141748)

gh-141570: can_colorize: Expect fileno() to raise OSError, as documented (#141716)

In Fedora, we've been given a slightly incomplete reproducer for a problematic
Python 3.14 color-related change in argparse that leads to an exception when
Python is used from mod_wsgi: https://bugzilla.redhat.com/2414940

mod_wsgi replaces sys.stdout with a custom object that raises OSError on .fileno():

8460dbfcd5/src/server/wsgi_logger.c (L434-L440)

This should be supported, as the documentation of fileno explicitly says:

> An OSError is raised if the IO object does not use a file descriptor.

https://docs.python.org/3.14/library/io.html#io.IOBase.fileno

The previously expected exception inherits from OSError,
so it is still expected.

Fixes https://github.com/python/cpython/issues/141570



(cherry picked from commit 96f496a949)

Co-authored-by: Miro Hrončok <miro@hroncok.cz>
Co-authored-by: Cody Maloney <cmaloney@users.noreply.github.com>

Lib/_colorize.py

@@ -1,5 +1,4 @@
 from __future__ import annotations
-import io
 import os
 import sys
 
@@ -116,5 +115,5 @@ def _safe_getenv(k: str, fallback: str | None = None) -> str | None:
 
     try:
         return os.isatty(file.fileno())
-    except io.UnsupportedOperation:
+    except OSError:
         return hasattr(file, "isatty") and file.isatty()