JBR-6036 Wayland: Cannot invoke "java.awt.Component.getWidth()" becau…

…se "popupParent" is null

Not all POPUP Window's have their parent set. And only those who do
shall be treated as popups in the Wayland's sense.

src/java.desktop/unix/classes/sun/awt/wl/WLComponentPeer.java

@@ -234,11 +234,11 @@ protected void wlSetVisible(boolean v) {
         this.visible = v;
         if (this.visible) {
             final String title = getTitle();
-            final boolean isPopup = target instanceof Window window && window.getType() == Window.Type.POPUP;
+            final boolean isWlPopup = targetIsWlPopup();
             final int thisWidth = getWidth();
             final int thisHeight = getHeight();
             performLocked(() -> {
-                if (isPopup) {
+                if (isWlPopup) {
                     Window popup = (Window) target;
                     final Component popupParent = AWTAccessor.getWindowAccessor().getPopupParent(popup);
                     final int parentWidth = popupParent.getWidth();
@@ -281,6 +281,16 @@ protected void wlSetVisible(boolean v) {
         }
     }
 
+    /**
+     * Returns true if our target should be treated as a popup in Wayland's sense,
+     * i.e. it has to have a parent to position relative to.
+     */
+    private boolean targetIsWlPopup() {
+        return target instanceof Window window
+                && window.getType() == Window.Type.POPUP
+                && AWTAccessor.getWindowAccessor().getPopupParent(window) != null;
+    }
+
     void configureWLSurface() {
         synchronized (sizeLock) {
             if (log.isLoggable(PlatformLogger.Level.FINE)) {
@@ -1002,11 +1012,11 @@ void notifyConfigured(int newWidth, int newHeight, boolean active, boolean maxim
             log.fine(String.format("%s configured to %dx%d", this, newWidth, newHeight));
         }
 
-        final boolean isPopup = target instanceof Window window && window.getType() == Window.Type.POPUP;
+        boolean isWlPopup = targetIsWlPopup();
 
         if (newWidth != 0 && newHeight != 0) performUnlocked(() ->target.setSize(newWidth, newHeight));
 
-        if (newWidth == 0 || newHeight == 0 || isPopup) {
+        if (newWidth == 0 || newHeight == 0 || isWlPopup) {
             // From xdg-shell.xml: "If the width or height arguments are zero,
             // it means the client should decide its own window dimension".