Fix inputhook implementation to be compatible with asyncio.run().

`asyncio.get_event_loop()` got deprecated. So we can't install an event loop
with inputhook upfront and then use in in prompt_toolkit. Instead, we can take
the inputhook as an argument in `Application.run()` and `PromptSession.run()`,
and install it in the event loop that we create ourselves using
`asyncio.run()`.

Author: jonathanslenders

.github/workflows/test.yaml

@@ -36,8 +36,9 @@ jobs:
       - name: Tests
         run: |
           coverage run -m pytest
-      - name: Mypy
-        # Check wheather the imports were sorted correctly.
+      - if: "matrix.python-version != '3.7'"
+        name: Mypy
+        # Check whether the imports were sorted correctly.
         # When this fails, please run ./tools/sort-imports.sh
         run: |
           mypy --strict src/prompt_toolkit --platform win32

src/prompt_toolkit/application/application.py

@@ -40,7 +40,9 @@
 from prompt_toolkit.data_structures import Size
 from prompt_toolkit.enums import EditingMode
 from prompt_toolkit.eventloop import (
+    InputHook,
     get_traceback_from_context,
+    new_eventloop_with_inputhook,
     run_in_executor_with_context,
 )
 from prompt_toolkit.eventloop.utils import call_soon_threadsafe
@@ -898,13 +900,12 @@ def run(
         set_exception_handler: bool = True,
         handle_sigint: bool = True,
         in_thread: bool = False,
+        inputhook: InputHook | None = None,
     ) -> _AppResult:
         """
         A blocking 'run' call that waits until the UI is finished.
 
-        This will start the current asyncio event loop. If no loop is set for
-        the current thread, then it will create a new loop. If a new loop was
-        created, this won't close the new loop (if `in_thread=False`).
+        This will run the application in a fresh asyncio event loop.
 
         :param pre_run: Optional callable, which is called right after the
             "reset" of the application.
@@ -937,6 +938,7 @@ def run_in_thread() -> None:
                         set_exception_handler=set_exception_handler,
                         # Signal handling only works in the main thread.
                         handle_sigint=False,
+                        inputhook=inputhook,
                     )
                 except BaseException as e:
                     exception = e
@@ -954,23 +956,18 @@ def run_in_thread() -> None:
             set_exception_handler=set_exception_handler,
             handle_sigint=handle_sigint,
         )
-        try:
-            # See whether a loop was installed already. If so, use that. That's
-            # required for the input hooks to work, they are installed using
-            # `set_event_loop`.
-            if sys.version_info < (3, 10):
-                loop = asyncio.get_event_loop()
-            else:
-                try:
-                    loop = asyncio.get_running_loop()
-                except RuntimeError:
-                    loop = asyncio.new_event_loop()
-        except RuntimeError:
+        if inputhook is None:
             # No loop installed. Run like usual.
             return asyncio.run(coro)
         else:
-            # Use existing loop.
-            return loop.run_until_complete(coro)
+            # Create new event loop with given input hook and run the app.
+            # In Python 3.12, we can use asyncio.run(loop_factory=...)
+            # For now, use `run_until_complete()`.
+            loop = new_eventloop_with_inputhook(inputhook)
+            result = loop.run_until_complete(coro)
+            loop.run_until_complete(loop.shutdown_asyncgens())
+            loop.close()
+            return result
 
     def _handle_exception(
         self, loop: AbstractEventLoop, context: dict[str, Any]

src/prompt_toolkit/application/dummy.py

@@ -2,6 +2,7 @@
 
 from typing import Callable
 
+from prompt_toolkit.eventloop import InputHook
 from prompt_toolkit.formatted_text import AnyFormattedText
 from prompt_toolkit.input import DummyInput
 from prompt_toolkit.output import DummyOutput
@@ -28,6 +29,7 @@ def run(
         set_exception_handler: bool = True,
         handle_sigint: bool = True,
         in_thread: bool = False,
+        inputhook: InputHook | None = None,
     ) -> None:
         raise NotImplementedError("A DummyApplication is not supposed to run.")
 

src/prompt_toolkit/eventloop/__init__.py

@@ -2,6 +2,7 @@
 
 from .async_generator import aclosing, generator_to_async_generator
 from .inputhook import (
+    InputHook,
     InputHookContext,
     InputHookSelector,
     new_eventloop_with_inputhook,
@@ -22,6 +23,7 @@
     "call_soon_threadsafe",
     "get_traceback_from_context",
     # Inputhooks.
+    "InputHook",
     "new_eventloop_with_inputhook",
     "set_eventloop_with_inputhook",
     "InputHookSelector",

src/prompt_toolkit/eventloop/inputhook.py

@@ -39,14 +39,32 @@
     "set_eventloop_with_inputhook",
     "InputHookSelector",
     "InputHookContext",
+    "InputHook",
 ]
 
 if TYPE_CHECKING:
     from _typeshed import FileDescriptorLike
+    from typing_extensions import TypeAlias
 
     _EventMask = int
 
 
+class InputHookContext:
+    """
+    Given as a parameter to the inputhook.
+    """
+
+    def __init__(self, fileno: int, input_is_ready: Callable[[], bool]) -> None:
+        self._fileno = fileno
+        self.input_is_ready = input_is_ready
+
+    def fileno(self) -> int:
+        return self._fileno
+
+
+InputHook: TypeAlias = Callable[[InputHookContext], None]
+
+
 def new_eventloop_with_inputhook(
     inputhook: Callable[[InputHookContext], None]
 ) -> AbstractEventLoop:
@@ -64,6 +82,8 @@ def set_eventloop_with_inputhook(
     """
     Create a new event loop with the given inputhook, and activate it.
     """
+    # Deprecated!
+
     loop = new_eventloop_with_inputhook(inputhook)
     asyncio.set_event_loop(loop)
     return loop
@@ -168,16 +188,3 @@ def close(self) -> None:
 
     def get_map(self) -> Mapping[FileDescriptorLike, SelectorKey]:
         return self.selector.get_map()
-
-
-class InputHookContext:
-    """
-    Given as a parameter to the inputhook.
-    """
-
-    def __init__(self, fileno: int, input_is_ready: Callable[[], bool]) -> None:
-        self._fileno = fileno
-        self.input_is_ready = input_is_ready
-
-    def fileno(self) -> int:
-        return self._fileno

src/prompt_toolkit/layout/controls.py

@@ -449,7 +449,7 @@ def mouse_handler(self, mouse_event: MouseEvent) -> NotImplementedOrNone:
                             # Handler found. Call it.
                             # (Handler can return NotImplemented, so return
                             # that result.)
-                            handler = item[2]  # type: ignore
+                            handler = item[2]
                             return handler(mouse_event)
                         else:
                             break

src/prompt_toolkit/shortcuts/prompt.py

@@ -45,6 +45,7 @@
 )
 from prompt_toolkit.document import Document
 from prompt_toolkit.enums import DEFAULT_BUFFER, SEARCH_BUFFER, EditingMode
+from prompt_toolkit.eventloop import InputHook
 from prompt_toolkit.filters import (
     Condition,
     FilterOrBool,
@@ -892,6 +893,7 @@ def prompt(
         set_exception_handler: bool = True,
         handle_sigint: bool = True,
         in_thread: bool = False,
+        inputhook: InputHook | None = None,
     ) -> _T:
         """
         Display the prompt.
@@ -1025,6 +1027,7 @@ class itself. For these, passing in ``None`` will keep the current
             set_exception_handler=set_exception_handler,
             in_thread=in_thread,
             handle_sigint=handle_sigint,
+            inputhook=inputhook,
         )
 
     @contextmanager
@@ -1393,11 +1396,14 @@ def prompt(
     enable_open_in_editor: FilterOrBool | None = None,
     tempfile_suffix: str | Callable[[], str] | None = None,
     tempfile: str | Callable[[], str] | None = None,
-    in_thread: bool = False,
     # Following arguments are specific to the current `prompt()` call.
     default: str = "",
     accept_default: bool = False,
     pre_run: Callable[[], None] | None = None,
+    set_exception_handler: bool = True,
+    handle_sigint: bool = True,
+    in_thread: bool = False,
+    inputhook: InputHook | None = None,
 ) -> str:
     """
     The global `prompt` function. This will create a new `PromptSession`
@@ -1448,7 +1454,10 @@ def prompt(
         default=default,
         accept_default=accept_default,
         pre_run=pre_run,
+        set_exception_handler=set_exception_handler,
+        handle_sigint=handle_sigint,
         in_thread=in_thread,
+        inputhook=inputhook,
     )