LabelScanStoreHaIT can replace label index extension

And does so by only removing all currently loaded label index extensions
before adding the specific extension it wants.

community/kernel/src/main/java/org/neo4j/graphdb/factory/GraphDatabaseFactoryState.java

@@ -21,8 +21,10 @@
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Predicate;
 
 import org.neo4j.graphdb.security.URLAccessRule;
 import org.neo4j.helpers.Service;
@@ -39,13 +41,14 @@ public class GraphDatabaseFactoryState
     private final List<KernelExtensionFactory<?>> kernelExtensions;
     private Monitors monitors;
     private LogProvider userLogProvider;
-    private Map<String,URLAccessRule> urlAccessRules;
+    private final Map<String,URLAccessRule> urlAccessRules;
 
-    public GraphDatabaseFactoryState() {
+    public GraphDatabaseFactoryState()
+    {
         settingsClasses = new ArrayList<>();
         settingsClasses.add( GraphDatabaseSettings.class );
         kernelExtensions = new ArrayList<>();
-        for ( KernelExtensionFactory factory : Service.load( KernelExtensionFactory.class ) )
+        for ( KernelExtensionFactory<?> factory : Service.load( KernelExtensionFactory.class ) )
         {
             kernelExtensions.add( factory );
         }
@@ -67,6 +70,19 @@ public Iterable<KernelExtensionFactory<?>> getKernelExtension()
         return kernelExtensions;
     }
 
+    public void removeKernelExtensions( Predicate<KernelExtensionFactory<?>> toRemove )
+    {
+        Iterator<KernelExtensionFactory<?>> iterator = kernelExtensions.iterator();
+        while ( iterator.hasNext() )
+        {
+            KernelExtensionFactory<?> extension = iterator.next();
+            if ( toRemove.test( extension ) )
+            {
+                iterator.remove();
+            }
+        }
+    }
+
     public void setKernelExtensions( Iterable<KernelExtensionFactory<?>> newKernelExtensions )
     {
         kernelExtensions.clear();

enterprise/ha/src/test/java/org/neo4j/graphdb/factory/TestHighlyAvailableGraphDatabaseFactory.java

@@ -20,6 +20,7 @@
 package org.neo4j.graphdb.factory;
 
 import java.util.Collections;
+import java.util.function.Predicate;
 
 import org.neo4j.kernel.extension.KernelExtensionFactory;
 import org.neo4j.kernel.impl.ha.ClusterManager;
@@ -50,4 +51,10 @@ public TestHighlyAvailableGraphDatabaseFactory setKernelExtensions( Iterable<Ker
         getCurrentState().setKernelExtensions( newKernelExtensions );
         return this;
     }
+
+    public TestHighlyAvailableGraphDatabaseFactory removeKernelExtensions( Predicate<KernelExtensionFactory<?>> toRemove )
+    {
+        getCurrentState().removeKernelExtensions( toRemove );
+        return this;
+    }
 }

enterprise/ha/src/test/java/org/neo4j/kernel/api/impl/labelscan/LabelScanStoreHaIT.java

@@ -24,11 +24,10 @@
 import org.junit.Rule;
 import org.junit.Test;
 
-import java.util.Collections;
-
 import org.neo4j.graphdb.GraphDatabaseService;
 import org.neo4j.graphdb.Label;
 import org.neo4j.graphdb.Transaction;
+import org.neo4j.graphdb.factory.GraphDatabaseSettings;
 import org.neo4j.graphdb.factory.TestHighlyAvailableGraphDatabaseFactory;
 import org.neo4j.kernel.api.labelscan.LabelScanStore;
 import org.neo4j.kernel.extension.KernelExtensionFactory;
@@ -40,6 +39,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+
 import static org.neo4j.helpers.collection.Iterators.count;
 import static org.neo4j.kernel.impl.ha.ClusterManager.allAvailabilityGuardsReleased;
 import static org.neo4j.kernel.impl.ha.ClusterManager.allSeesAllAsAvailable;
@@ -111,15 +111,18 @@ public void setUp()
     {
         KernelExtensionFactory<?> testExtension = labelScanStoreExtension( monitor );
         TestHighlyAvailableGraphDatabaseFactory factory = new TestHighlyAvailableGraphDatabaseFactory();
-        factory.addKernelExtensions( Collections.singletonList( testExtension ) );
+        factory.removeKernelExtensions( extension -> extension.getClass().getName().contains( "LabelScan" ) );
+        factory.addKernelExtension( testExtension );
         ClusterManager clusterManager = new ClusterManager.Builder( testDirectory.directory( "root" ) )
                 .withDbFactory( factory )
+                .withSharedSetting( GraphDatabaseSettings.label_index, labelIndexSettingName() )
                 .withStoreDirInitializer( ( serverId, storeDir ) -> {
                     if ( serverId == 1 )
                     {
                         GraphDatabaseService db = new TestGraphDatabaseFactory()
                                 .addKernelExtension( testExtension )
                                 .newEmbeddedDatabaseBuilder( storeDir.getAbsoluteFile() )
+                                .setConfig( GraphDatabaseSettings.label_index, labelIndexSettingName() )
                                 .newGraphDatabase();
                         try
                         {
@@ -141,6 +144,8 @@ public void setUp()
         cluster.await( allAvailabilityGuardsReleased() );
     }
 
+    protected abstract String labelIndexSettingName();
+
     protected abstract KernelExtensionFactory<?> labelScanStoreExtension( LabelScanStore.Monitor monitor );
 
     @After

enterprise/ha/src/test/java/org/neo4j/kernel/api/impl/labelscan/LuceneLabelScanStoreHaIT.java

@@ -19,6 +19,7 @@
  */
 package org.neo4j.kernel.api.impl.labelscan;
 
+import org.neo4j.graphdb.factory.GraphDatabaseSettings.LabelIndex;
 import org.neo4j.kernel.api.labelscan.LabelScanStore;
 import org.neo4j.kernel.extension.KernelExtensionFactory;
 
@@ -29,4 +30,10 @@ protected KernelExtensionFactory<?> labelScanStoreExtension( LabelScanStore.Moni
     {
         return new LuceneLabelScanStoreExtension( 100, monitor );
     }
+
+    @Override
+    protected String labelIndexSettingName()
+    {
+        return LabelIndex.LUCENE.name();
+    }
 }

enterprise/ha/src/test/java/org/neo4j/kernel/api/impl/labelscan/NativeLabelScanStoreHaIT.java

@@ -19,6 +19,7 @@
  */
 package org.neo4j.kernel.api.impl.labelscan;
 
+import org.neo4j.graphdb.factory.GraphDatabaseSettings.LabelIndex;
 import org.neo4j.kernel.api.labelscan.LabelScanStore;
 import org.neo4j.kernel.extension.KernelExtensionFactory;
 import org.neo4j.kernel.impl.api.scan.NativeLabelScanStoreExtension;
@@ -30,4 +31,10 @@ protected KernelExtensionFactory<?> labelScanStoreExtension( LabelScanStore.Moni
     {
         return new NativeLabelScanStoreExtension( 100, monitor );
     }
+
+    @Override
+    protected String labelIndexSettingName()
+    {
+        return LabelIndex.NATIVE.name();
+    }
 }