[Cocoa] Fix NPE when the press-and-hold accent menu inserts text

Picking an accent from macOS's press-and-hold menu in a Text, Combo or
Spinner with a verify listener failed with a NullPointerException when
the click came more than a moment after the key-up. The menu inserts
the text from the run loop while Display.sleep runs, so
NSApplication.currentEvent() is null, and
shouldChangeTextInRange_replacementString called type() on it.

Treat a missing event like a non-key event, so that verifyText gets
null, as it already does for a mouse event.

Fixes #3819

Assisted-by: Claude Opus 5.5 <noreply@anthropic.com>

Author: Jm6CnDDXBwFTakS

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Combo.java

@@ -1848,8 +1848,10 @@ boolean shouldChangeTextInRange_replacementString(long id, long sel, long affect
 	if (hooks (SWT.Verify)) {
 		String string = new NSString(replacementString).getString();
 		NSEvent currentEvent = display.application.currentEvent();
-		long type = currentEvent.type();
-		if (type != OS.NSKeyDown && type != OS.NSKeyUp) currentEvent = null;
+		if (currentEvent != null) {
+			long type = currentEvent.type();
+			if (type != OS.NSKeyDown && type != OS.NSKeyUp) currentEvent = null;
+		}
 		String newText = verifyText(string, (int)range.location, (int)(range.location+range.length), currentEvent);
 		if (newText == null) return false;
 		if (!string.equals(newText)) {

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Spinner.java

@@ -1032,8 +1032,10 @@ boolean shouldChangeTextInRange_replacementString(long id, long sel, long affect
 	if (hooks (SWT.Verify)) {
 		String text = new NSString(replacementString).getString();
 		NSEvent currentEvent = display.application.currentEvent();
-		long type = currentEvent.type();
-		if (type != OS.NSKeyDown && type != OS.NSKeyUp) currentEvent = null;
+		if (currentEvent != null) {
+			long type = currentEvent.type();
+			if (type != OS.NSKeyDown && type != OS.NSKeyUp) currentEvent = null;
+		}
 		String newText = verifyText(text, (int)range.location, (int)(range.location+range.length), currentEvent);
 		if (newText == null) return false;
 		if (text != newText) {

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Text.java

@@ -2372,8 +2372,10 @@ boolean shouldChangeTextInRange_replacementString(long id, long sel, long affect
 	String newText = text;
 	if (hooks (SWT.Verify)) {
 		NSEvent currentEvent = display.application.currentEvent();
-		long type = currentEvent.type();
-		if (type != OS.NSKeyDown && type != OS.NSKeyUp) currentEvent = null;
+		if (currentEvent != null) {
+			long type = currentEvent.type();
+			if (type != OS.NSKeyDown && type != OS.NSKeyUp) currentEvent = null;
+		}
 		newText = verifyText(text, (int)range.location, (int)(range.location+range.length),  currentEvent);
 	}
 	if (newText == null) return false;