keyutils: Work around broken Python 3.11.4 enum.Flag inversion

Take a detour via .value if on Qt 6, because Python 3.11.4 seems to be
unable to invert enum.Flag values with a mask set.

Fixes #7735

See:
- https://github.com/python/cpython/issues/105497
- https://www.riverbankcomputing.com/pipermail/pyqt/2023-June/045323.html

1 files changed, 21 insertions, 6 deletions

diff --git a/qutebrowser/keyinput/keyutils.py b/qutebrowser/keyinput/keyutils.py
index 2d3e11864..aecca59a8 100644
--- a/qutebrowser/keyinput/keyutils.py
+++ b/qutebrowser/keyinput/keyutils.py
@@ -260,7 +260,7 @@ def _modifiers_to_string(modifiers: _ModifierType) -> str:
     _assert_plain_modifier(modifiers)
     altgr = Qt.KeyboardModifier.GroupSwitchModifier
     if modifiers & altgr:
-        modifiers &= ~altgr  # type: ignore[assignment]
+        modifiers = _unset_modifier_bits(modifiers, altgr)
         result = 'AltGr+'
     else:
         result = ''
@@ -341,6 +341,21 @@ def _parse_single_key(keystr: str) -> str:
     return 'Shift+' + keystr if keystr.isupper() else keystr
 
 
+def _unset_modifier_bits(
+    modifiers: _ModifierType, mask: _ModifierType
+) -> _ModifierType:
+    """Unset all bits in modifiers which are given in mask.
+
+    Equivalent to modifiers & ~mask, but with a WORKAROUND with PyQt 6,
+    for a bug in Python 3.11.4 where that isn't possible with an enum.Flag...:
+    https://github.com/python/cpython/issues/105497
+    """
+    if machinery.IS_QT5:
+        return cast(_ModifierType, modifiers & ~mask)
+    return Qt.KeyboardModifier(  # type: ignore[unreachable]
+        modifiers.value & ~mask.value)
+
+
 @dataclasses.dataclass(frozen=True, order=True)
 class KeyInfo:
 
@@ -420,7 +435,7 @@ class KeyInfo:
 
         if self.key in _MODIFIER_MAP:
             # Don't return e.g. <Shift+Shift>
-            modifiers &= ~_MODIFIER_MAP[self.key]  # type: ignore[assignment]
+            modifiers = _unset_modifier_bits(modifiers, _MODIFIER_MAP[self.key])
         elif _is_printable(self.key):
             # "normal" binding
             if not key_string:  # pragma: no cover
@@ -487,7 +502,7 @@ class KeyInfo:
             return QKeyCombination(self.modifiers, key)
 
     def with_stripped_modifiers(self, modifiers: Qt.KeyboardModifier) -> "KeyInfo":
-        mods = self.modifiers & ~modifiers
+        mods = _unset_modifier_bits(self.modifiers, modifiers)
         return KeyInfo(key=self.key, modifiers=mods)
 
     def is_special(self) -> bool:
@@ -670,7 +685,7 @@ class KeySequence:
 
         # We always remove Qt.KeyboardModifier.GroupSwitchModifier because QKeySequence has no
         # way to mention that in a binding anyways...
-        modifiers &= ~Qt.KeyboardModifier.GroupSwitchModifier
+        modifiers = _unset_modifier_bits(modifiers, Qt.KeyboardModifier.GroupSwitchModifier)
 
         # We change Qt.Key.Key_Backtab to Key_Tab here because nobody would
         # configure "Shift-Backtab" in their config.
@@ -703,10 +718,10 @@ class KeySequence:
             if modifiers & Qt.KeyboardModifier.ControlModifier and modifiers & Qt.KeyboardModifier.MetaModifier:
                 pass
             elif modifiers & Qt.KeyboardModifier.ControlModifier:
-                modifiers &= ~Qt.KeyboardModifier.ControlModifier
+                modifiers = _unset_modifier_bits(modifiers, Qt.KeyboardModifier.ControlModifier)
                 modifiers |= Qt.KeyboardModifier.MetaModifier
             elif modifiers & Qt.KeyboardModifier.MetaModifier:
-                modifiers &= ~Qt.KeyboardModifier.MetaModifier
+                modifiers = _unset_modifier_bits(modifiers, Qt.KeyboardModifier.MetaModifier)
                 modifiers |= Qt.KeyboardModifier.ControlModifier
 
         infos = list(self)