1 files changed, 15 insertions, 4 deletions
diff --git a/qutebrowser/keyinput/keyutils.py b/qutebrowser/keyinput/keyutils.py
index dfe4fb3ff..a56efeab8 100644
--- a/qutebrowser/keyinput/keyutils.py
+++ b/qutebrowser/keyinput/keyutils.py
@@ -48,11 +48,19 @@ def _assert_plain_modifier(key):
     assert not key & ~Qt.KeyboardModifierMask, hex(key)
 
 
-def is_printable(key):
+def _is_printable(key):
     _assert_plain_key(key)
     return key <= 0xff and key not in [Qt.Key_Space, 0x0]
 
 
+def is_special(key, modifiers):
+    """Check whether this key requires special key syntax."""
+    _assert_plain_key(key)
+    _assert_plain_modifier(modifiers)
+    return not (_is_printable(key) and
+                modifiers in [Qt.ShiftModifier, Qt.NoModifier])
+
+
 def is_modifier_key(key):
     """Test whether the given key is a modifier.
 
@@ -277,7 +285,7 @@ class KeyInfo:
         if self.key in _MODIFIER_MAP:
             # Don't return e.g. <Shift+Shift>
             modifiers &= ~_MODIFIER_MAP[self.key]
-        elif is_printable(self.key):
+        elif _is_printable(self.key):
             # "normal" binding
             if not key_string:  # pragma: no cover
                 raise ValueError("Got empty string for key 0x{:x}!"
@@ -285,14 +293,17 @@ class KeyInfo:
 
             assert len(key_string) == 1, key_string
             if self.modifiers == Qt.ShiftModifier:
+                assert not is_special(self.key, self.modifiers)
                 return key_string.upper()
             elif self.modifiers == Qt.NoModifier:
+                assert not is_special(self.key, self.modifiers)
                 return key_string.lower()
             else:
                 # Use special binding syntax, but <Ctrl-a> instead of <Ctrl-A>
                 key_string = key_string.lower()
 
         # "special" binding
+        assert is_special(self.key, self.modifiers)
         modifier_string = _modifiers_to_string(modifiers)
         return '<{}{}>'.format(modifier_string, key_string)
 
@@ -309,7 +320,7 @@ class KeyInfo:
 
         if self.key in control:
             return control[self.key]
-        elif not is_printable(self.key):
+        elif not _is_printable(self.key):
             return ''
 
         text = QKeySequence(self.key).toString()
@@ -490,7 +501,7 @@ class KeySequence:
         # In addition, Shift also *is* relevant when other modifiers are
         # involved. Shift-Ctrl-X should not be equivalent to Ctrl-X.
         if (modifiers == Qt.ShiftModifier and
-                is_printable(ev.key()) and
+                _is_printable(ev.key()) and
                 not ev.text().isupper()):
             modifiers = Qt.KeyboardModifiers()