Check for optimizations when looking for missing updates (#18317)

A recently merged patch leaves out information from hierarchyInfo for
empty connectors with state changes. This must be taken into account
when looking for disappeared connectors that do not cause any hierarchy
change to be sent.

Change-Id: I9ae7150341a83798141d0a2806ee81cafe7c2f9a

1 files changed, 40 insertions, 1 deletions

diff --git a/server/src/com/vaadin/ui/ConnectorTracker.java b/server/src/com/vaadin/ui/ConnectorTracker.java
index a060702319..159bd09c0d 100644
--- a/server/src/com/vaadin/ui/ConnectorTracker.java
+++ b/server/src/com/vaadin/ui/ConnectorTracker.java
@@ -368,7 +368,34 @@ public class ConnectorTracker implements Serializable {
             }
 
             if (!hierachyInfo.hasKey(firstVisibleParent.getConnectorId())) {
-                return false;
+                /*
+                 * No hierarchy change about to be sent, but this might be
+                 * because of an optimization that omits explicit hierarchy
+                 * changes for empty connectors that have state changes.
+                 */
+                if (hasVisibleChild(firstVisibleParent)) {
+                    // Not the optimization case if the parent has visible
+                    // children
+                    return false;
+                }
+
+                attributeName = ConnectorHierarchyWriter.class.getName()
+                        + ".stateUpdateConnectors";
+                Object stateUpdateConnectorsObj = request
+                        .getAttribute(attributeName);
+                if (stateUpdateConnectorsObj instanceof Set<?>) {
+                    Set<?> stateUpdateConnectors = (Set<?>) stateUpdateConnectorsObj;
+                    if (!stateUpdateConnectors.contains(firstVisibleParent
+                            .getConnectorId())) {
+                        // Not the optimization case if the parent is not marked
+                        // as dirty
+                        return false;
+                    }
+                } else {
+                    getLogger().warning(
+                            "Request attribute " + attributeName
+                                    + " is not a Set");
+                }
             }
         } else {
             getLogger().warning(
@@ -379,6 +406,18 @@ public class ConnectorTracker implements Serializable {
         return true;
     }
 
+    private static boolean hasVisibleChild(ClientConnector parent) {
+        Iterator<? extends ClientConnector> iterator = AbstractClientConnector
+                .getAllChildrenIterable(parent).iterator();
+        while (iterator.hasNext()) {
+            ClientConnector child = iterator.next();
+            if (LegacyCommunicationManager.isConnectorVisibleToClient(child)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     private ClientConnector findFirstVisibleParent(ClientConnector connector) {
         while (connector != null) {
             connector = connector.getParent();