gh-127947: Repeat PyREPL key events on Windows when wRepeatCount > 1

Lib/_pyrepl/windows_console.py

@@ -132,6 +132,7 @@ def __init__(
         self.height = 25
         self.__offset = 0
         self.event_queue: deque[Event] = deque()
+        self.key_repeat_queue: deque[Event] = deque()
         try:
             self.out = io._WindowsConsoleIO(self.output_fd, "w")  # type: ignore[attr-defined]
         except ValueError:
@@ -394,6 +395,9 @@ def get_event(self, block: bool = True) -> Event | None:
         """Return an Event instance.  Returns None if |block| is false
         and there is no event pending, otherwise waits for the
         completion of an event."""
+        if self.key_repeat_queue:
+            return self.key_repeat_queue.pop()
+
         if self.event_queue:
             return self.event_queue.pop()
 
@@ -411,37 +415,47 @@ def get_event(self, block: bool = True) -> Event | None:
                     continue
                 return None
 
-            key_event = rec.Event.KeyEvent
-            raw_key = key = key_event.uChar.UnicodeChar
-
-            if key == "\r":
-                # Make enter unix-like
-                return Event(evt="key", data="\n", raw=b"\n")
-            elif key_event.wVirtualKeyCode == 8:
-                # Turn backspace directly into the command
-                key = "backspace"
-            elif key == "\x00":
-                # Handle special keys like arrow keys and translate them into the appropriate command
-                key = VK_MAP.get(key_event.wVirtualKeyCode)
-                if key:
-                    if key_event.dwControlKeyState & CTRL_ACTIVE:
-                        key = f"ctrl {key}"
-                    elif key_event.dwControlKeyState & ALT_ACTIVE:
-                        # queue the key, return the meta command
-                        self.event_queue.insert(0, Event(evt="key", data=key, raw=key))
-                        return Event(evt="key", data="\033")  # keymap.py uses this for meta
-                    return Event(evt="key", data=key, raw=key)
-                if block:
-                    continue
+            event = self._event_from_keyevent(rec.Event.KeyEvent)
+
+            if event is not None:
+                # Queue this key event to be repeated if wRepeatCount > 1, such as when a 'dead key' is pressed twice
+                for _ in range(rec.Event.KeyEvent.wRepeatCount - 1):
+                    self.key_repeat_queue.appendleft(event)
+            elif block:
+                # The key event didn't ectually type a character, block until next event
+                continue
+
+            return event
+
+    def _event_from_keyevent(self, key_event: KeyEvent) -> Event | None:
+        raw_key = key = key_event.uChar.UnicodeChar
+
+        if key == "\r":
+            # Make enter unix-like
+            return Event(evt="key", data="\n", raw=b"\n")
+        elif key_event.wVirtualKeyCode == 8:
+            # Turn backspace directly into the command
+            key = "backspace"
+        elif key == "\x00":
+            # Handle special keys like arrow keys and translate them into the appropriate command
+            key = VK_MAP.get(key_event.wVirtualKeyCode)
+            if key:
+                if key_event.dwControlKeyState & CTRL_ACTIVE:
+                    key = f"ctrl {key}"
+                elif key_event.dwControlKeyState & ALT_ACTIVE:
+                    # queue the key, return the meta command
+                    self.event_queue.insert(0, Event(evt="key", data=key, raw=key))
+                    return Event(evt="key", data="\033")  # keymap.py uses this for meta
+                return Event(evt="key", data=key, raw=key)
 
-                return None
+            return None
 
-            if key_event.dwControlKeyState & ALT_ACTIVE:
-                # queue the key, return the meta command
-                self.event_queue.insert(0, Event(evt="key", data=key, raw=raw_key))
-                return Event(evt="key", data="\033")  # keymap.py uses this for meta
+        if key_event.dwControlKeyState & ALT_ACTIVE:
+            # queue the key, return the meta command
+            self.event_queue.insert(0, Event(evt="key", data=key, raw=raw_key))
+            return Event(evt="key", data="\033")  # keymap.py uses this for meta
 
-            return Event(evt="key", data=key, raw=raw_key)
+        return Event(evt="key", data=key, raw=raw_key)
 
     def push_char(self, char: int | bytes) -> None:
         """
@@ -489,7 +503,7 @@ def wait(self, timeout: float | None) -> bool:
         # Poor man's Windows select loop
         start_time = time.time()
         while True:
-            if msvcrt.kbhit(): # type: ignore[attr-defined]
+            if msvcrt.kbhit() or self.key_repeat_queue: # type: ignore[attr-defined]
                 return True
             if timeout and time.time() - start_time > timeout / 1000:
                 return False

Lib/test/test_pyrepl/test_windows_console.py

@@ -22,15 +22,42 @@
         MOVE_UP,
         MOVE_DOWN,
         ERASE_IN_LINE,
+        INPUT_RECORD,
+        ConsoleEvent,
+        KeyEvent,
+        Char,
+        KEY_EVENT
     )
 except ImportError:
     pass
 
 
+def make_input_record(character: str, repeat_count: int = 1, virtual_keycode: int = 0):
+    assert len(character) == 1
+
+    rec = INPUT_RECORD()
+    rec.EventType = KEY_EVENT
+    rec.Event = ConsoleEvent()
+    rec.Event.KeyEvent = KeyEvent()
+
+    rec.Event.KeyEvent.bKeyDown = True
+    rec.Event.KeyEvent.wRepeatCount = repeat_count
+    rec.Event.KeyEvent.wVirtualKeyCode = virtual_keycode  # Only used for special keys (see VK_MAP in windows_console.py)
+    rec.Event.KeyEvent.wVirtualScanCode = 0  # Not used by WindowsConsole
+    rec.Event.KeyEvent.uChar = Char()
+    rec.Event.KeyEvent.uChar.UnicodeChar = character
+    rec.Event.KeyEvent.dwControlKeyState = False
+    return rec
+
+
 class WindowsConsoleTests(TestCase):
-    def console(self, events, **kwargs) -> Console:
+    def console(self, events, mock_input_record=False, **kwargs) -> Console:
         console = WindowsConsole()
-        console.get_event = MagicMock(side_effect=events)
+        if mock_input_record:
+            # Mock the lower level _read_input method instead of get_event
+            console._read_input = MagicMock(side_effect=events)
+        else:
+            console.get_event = MagicMock(side_effect=events)
         console._scroll = MagicMock()
         console._hide_cursor = MagicMock()
         console._show_cursor = MagicMock()
@@ -49,6 +76,9 @@ def console(self, events, **kwargs) -> Console:
     def handle_events(self, events: Iterable[Event], **kwargs):
         return handle_all_events(events, partial(self.console, **kwargs))
 
+    def handle_input_records(self, input_records: Iterable[INPUT_RECORD], **kwargs):
+        return handle_all_events(input_records, partial(self.console, mock_input_record=True, **kwargs))
+
     def handle_events_narrow(self, events):
         return self.handle_events(events, width=5)
 
@@ -58,6 +88,21 @@ def handle_events_short(self, events):
     def handle_events_height_3(self, events):
         return self.handle_events(events, height=3)
 
+    def test_key_records_no_repeat(self):
+        input_records = [make_input_record(c) for c in "12+34"]
+        _, con = self.handle_input_records(input_records)
+        expected_calls = [call(c.encode()) for c in "12+34"]
+        con.out.write.assert_has_calls(expected_calls)
+        con.restore()
+
+    def test_key_records_with_repeat(self):
+        input_records = [make_input_record(c, 2) for c in "12+34"]
+        input_records.append(make_input_record("5", 3))
+        _, con = self.handle_input_records(input_records)
+        expected_calls = [call(c.encode()) for c in "1122++3344555"]
+        con.out.write.assert_has_calls(expected_calls)
+        con.restore()
+
     def test_simple_addition(self):
         code = "12+34"
         events = code_to_events(code)

Misc/ACKS

@@ -166,6 +166,7 @@ Jay Berry
 Eric Beser
 Steven Bethard
 Stephen Bevan
+Simon van Bezooijen
 Ron Bickers
 Natalia B. Bidart
 Adrian von Bidder

Misc/NEWS.d/next/Library/2024-12-14-16-28-33.gh-issue-127947.2W5rYh.rst

@@ -0,0 +1 @@
+Fix double dead key presses in PyREPL being typed just once into Windows Terminal.