macOS: Send key press as QKeyEvent if input context doesn't consume it

If IM is enabled we send key events through the macOS text input system,
and we do this for all key pressed, including the ones with modifiers
pressed. The latter allows the input method to respond to shortcut
key combinations to switch its own mode or do more advanced operations
on the text.

We were relying on the IM to call doCommandBySelector with a noop
selector if the shortcut didn't match any of its own internal key
sequences, but this fails for key events with more than one modifier
pressed.

Instead of using [NSView interpretKeyEvents:] to pass the key event
to the system IM we now go directly to the NSInputContext, which the
former method is just a wrapper for. This allows us to use the result
of [NSInputContext handleEvent:] to determine if the system IM consumed
the event or not. For key events with multiple modifiers this will be
false, which we interpret to send the event as a regular QKeyEvent
instead.

Fixes: QTBUG-123848
Fixes: QTBUG-106516
Pick-to: 6.7 6.5 6.2
Change-Id: I14a43c2029149514515dd9ece881aed3f6500a4e
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/plugins/platforms/cocoa/qnsview_keys.mm b/src/plugins/platforms/cocoa/qnsview_keys.mm
index 118678ffa5..d9d9f0a794 100644
--- a/src/plugins/platforms/cocoa/qnsview_keys.mm
+++ b/src/plugins/platforms/cocoa/qnsview_keys.mm
@@ -94,7 +94,10 @@ static bool isSpecialKey(const QString &text)
 
                     qCDebug(lcQpaKeys) << "Interpreting key event for focus object" << focusObject;
                     m_currentlyInterpretedKeyEvent = nsevent;
-                    [self interpretKeyEvents:@[nsevent]];
+                    if (![self.inputContext handleEvent:nsevent]) {
+                        qCDebug(lcQpaKeys) << "Input context did not consume event";
+                        m_sendKeyEvent = true;
+                    }
                     m_currentlyInterpretedKeyEvent = 0;
                     didInterpretKeyEvent = true;