fix: Clear O_NONBLOCK flag after using ainput()

This is to ensure we can still use regular blocking IO such as
input() and print() after using ainput.

Fixes #17, #19

src/loveletter_cli/session.py

@@ -9,7 +9,6 @@
 
 import more_itertools as mitt
 import valid8
-from aioconsole import ainput
 from multimethod import multimethod
 
 import loveletter.game
@@ -22,6 +21,7 @@
 from loveletter_cli.exceptions import Restart
 from loveletter_cli.server_process import ServerProcess
 from loveletter_cli.ui import (
+    ainput,
     async_ask_valid_input,
     draw_game,
     pause,

src/loveletter_cli/ui/input.py

@@ -1,11 +1,13 @@
 import enum
 import functools
+import os
+import sys
 import textwrap
 from typing import Callable, Tuple, Type, TypeVar
 
+import aioconsole
 import more_itertools
 import valid8
-from aioconsole import ainput
 
 from .misc import printable_width
 
@@ -14,6 +16,21 @@
 _DEFAULT = object()
 
 
+# Define ainput() based on OS: if the OS uses the O_NONBLOCK flag, we have to
+# clear it after every call to ainput() to ensure compatibility with blocking
+# IO such as print() and input().
+if hasattr(os, "set_blocking"):
+
+    @functools.wraps(aioconsole.ainput)
+    async def ainput(*args, **kwargs):
+        result = await aioconsole.ainput(*args, **kwargs)
+        os.set_blocking(sys.stdin.fileno(), True)
+        return result
+
+else:
+    ainput = aioconsole.ainput
+
+
 def ask_valid_input(*args, **kwargs) -> _T:
     error_message, parser, prompt, validation_errors = _ask_valid_input_parse_args(
         *args, **kwargs
@@ -162,4 +179,6 @@ async def pause() -> None:
     # the user has to enter twice before input is detected;
     # but the asynchronous nature is needed to ensure other events are handled in time
     # (e.g. when the connection is lost).
+    # Also caused trouble on Linux and Unix regarding the O_NONBLOCK flag
+    # (see #17 and #19) but this has been fixed.
     await ainput("Enter something to continue... ")