Don't close sys.stdin with quit() if sys.stdin wraps fd 0. Otherwise it will raise a warning: Lib/io.py:1221: RuntimeWarning: Trying to close unclosable fd

Lib/site.py

@@ -247,7 +247,12 @@ def setquit():
             # Shells like IDLE catch the SystemExit, but listen when their
             # stdin wrapper is closed.
             try:
-                sys.stdin.close()
+                fd = -1
+                if hasattr(sys.stdin, "fileno"):
+                    fd = sys.stdin.fileno()
+                if fd != 0:
+                    # Don't close stdin if it wraps fd 0
+                    sys.stdin.close()
             except:
                 pass
             raise SystemExit(code)