don't require IO for redirect_stdout

#14903

Author: beauxq

stdlib/contextlib.pyi

@@ -141,14 +141,23 @@ class suppress(AbstractContextManager[None, bool]):
         self, exctype: type[BaseException] | None, excinst: BaseException | None, exctb: TracebackType | None
     ) -> bool: ...
 
-class _RedirectStream(AbstractContextManager[_T_io, None]):
-    def __init__(self, new_target: _T_io) -> None: ...
+# This is trying to describe what is needed for (most?) uses
+# of `redirect_stdout` and `redirect_stderr`.
+# https://github.com/python/typeshed/issues/14903
+class _SupportsRedirect:
+    def write(self, s: str, /) -> int: ...
+    def flush(self) -> None: ...
+
+_SupportsRedirectT = TypeVar("_SupportsRedirectT", bound=_SupportsRedirect)
+
+class _RedirectStream(AbstractContextManager[_SupportsRedirectT, None]):
+    def __init__(self, new_target: _SupportsRedirectT) -> None: ...
     def __exit__(
         self, exctype: type[BaseException] | None, excinst: BaseException | None, exctb: TracebackType | None
     ) -> None: ...
 
-class redirect_stdout(_RedirectStream[_T_io]): ...
-class redirect_stderr(_RedirectStream[_T_io]): ...
+class redirect_stdout(_RedirectStream[_SupportsRedirectT]): ...
+class redirect_stderr(_RedirectStream[_SupportsRedirectT]): ...
 
 class _BaseExitStack(Generic[_ExitT_co]):
     def enter_context(self, cm: AbstractContextManager[_T, _ExitT_co]) -> _T: ...