Reset Combobox internal state (#11412)

issue in #11343 and #11385 is not reproducible on top this patch
Three different bugs are involved in this fix:
we bring the old fix(#11094) back and fixed the other related issues:
1) allow adding the same new item after dataProvider got reset, This is cause by the client side parameter `LastNewItemString`, it saves the value added before resetting. 
2) clear the pending newItem eagerly, so that the same value will not be added again.

2 files changed, 44 insertions, 16 deletions

diff --git a/client/src/main/java/com/vaadin/client/ui/VComboBox.java b/client/src/main/java/com/vaadin/client/ui/VComboBox.java
index fbac85c2af..50d4c6588c 100644
--- a/client/src/main/java/com/vaadin/client/ui/VComboBox.java
+++ b/client/src/main/java/com/vaadin/client/ui/VComboBox.java
@@ -23,7 +23,6 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
-import java.util.UUID;
 import java.util.logging.Logger;
 
 import com.google.gwt.animation.client.AnimationScheduler;
@@ -122,7 +121,7 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
          *            icon URI or null
          */
         public ComboBoxSuggestion(String key, String caption, String style,
-                String untranslatedIconUri) {
+                                  String untranslatedIconUri) {
             this.key = key;
             this.caption = caption;
             this.style = style;
@@ -1642,6 +1641,11 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
             performSelection(selectedKey, oldSuggestionTextMatchTheOldSelection,
                     !isWaitingForFilteringResponse() || popupOpenerClicked);
 
+            // currentSuggestion should be set to match the value of the
+            // ComboBox
+            resetCurrentSuggestionBasedOnServerResponse(selectedKey,
+                    selectedCaption, selectedIconUri);
+
             cancelPendingPostFiltering();
 
             setSelectedCaption(selectedCaption);
@@ -1649,6 +1653,22 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
             setSelectedItemIcon(selectedIconUri);
         }
 
+        /*
+         * Updates the current suggestion based on values provided by the
+         * server.
+         */
+        private void resetCurrentSuggestionBasedOnServerResponse(
+                String selectedKey, String selectedCaption,
+                String selectedIconUri) {
+            if (currentSuggestion == null
+                    && (selectedKey != null || selectedCaption != null)) {
+                currentSuggestion = new ComboBoxSuggestion(selectedKey,
+                        selectedCaption, "", selectedIconUri);
+            } else if (selectedKey == null && selectedCaption == null) {
+                currentSuggestion = null;
+            }
+        }
+
     }
 
     // TODO decide whether this should change - affects themes and v7
@@ -1707,7 +1727,9 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
     /** For internal use only. May be removed or replaced in the future. */
     public boolean initDone = false;
 
-    /** For internal use only. May be removed or replaced in the future. */
+    /**
+     * For internal use only. May be removed or replaced in the future.
+     */
     public String lastFilter = "";
 
     /**
@@ -1802,6 +1824,16 @@ public class VComboBox extends Composite implements Field, KeyDownHandler,
         return s.getMarginWidth() + s.getBorderWidth() + s.getPaddingWidth();
     }
 
+    /**
+     * This method will reset the saved item string which is added last time.
+     */
+    public void resetLastNewItemString() {
+        // Clean the temp string eagerly in order to re-add the same value again
+        // after data provider got reset.
+        // Fixes issue https://github.com/vaadin/framework/issues/11317
+        lastNewItemString = null;
+    }
+
     /*
      * (non-Javadoc)
      *
diff --git a/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java b/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java
index 3aa58083cf..2ef091569d 100644
--- a/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java
+++ b/client/src/main/java/com/vaadin/client/ui/combobox/ComboBoxConnector.java
@@ -130,11 +130,9 @@ public class ComboBoxConnector extends AbstractListingConnector
             getWidget().selectedOptionKey = null;
             getWidget().currentSuggestion = null;
         }
-        if (isNewItemStillPending()
-                && pendingNewItemValue == getState().selectedItemCaption) {
-            // no automated selection handling required
-            clearNewItemHandling();
-        }
+
+        clearNewItemHandlingIfMatch(getState().selectedItemCaption);
+
         getDataReceivedHandler().updateSelectionFromServer(
                 getState().selectedItemKey, getState().selectedItemCaption,
                 getState().selectedItemIcon);
@@ -188,10 +186,11 @@ public class ComboBoxConnector extends AbstractListingConnector
         if (itemValue != null && !itemValue.equals(pendingNewItemValue)) {
             // clear any previous handling as outdated
             clearNewItemHandling();
+
+            pendingNewItemValue = itemValue;
+            rpc.createNewItem(itemValue);
+            getDataReceivedHandler().clearPendingNavigation();
         }
-        pendingNewItemValue = itemValue;
-        rpc.createNewItem(itemValue);
-        getDataReceivedHandler().clearPendingNavigation();
     }
 
     /**
@@ -359,7 +358,7 @@ public class ComboBoxConnector extends AbstractListingConnector
 
         updateSuggestions(start, end);
         getWidget().setTotalSuggestions(getDataSource().size());
-
+        getWidget().resetLastNewItemString();
         getDataReceivedHandler().dataReceived();
     }
 
@@ -451,10 +450,7 @@ public class ComboBoxConnector extends AbstractListingConnector
      * versions.
      */
     private void clearNewItemHandling() {
-        // never clear pending value before it has been handled
-        if (!isNewItemStillPending()) {
-            pendingNewItemValue = null;
-        }
+        pendingNewItemValue = null;
     }
 
     /**