fix: prevent usage of VaadinRequest in access

VaadinRequest thread local is not available during a VaadinSession.access execution.
VaadinRequest is used to access the HTTP session wrapper, that can be obtained through
VaadinSession. The most important usage is however getting the update version header,
but the lookup can be done outside the access block.
This change also removes ClusterSupport registration in CurrentInstance becuase it
seems not to be used anywhere and furhtermore the thread local is set only on the
thread that calls serviceInit and never cleaned up.

Fixes #148

kubernetes-kit-starter/src/main/java/com/vaadin/kubernetes/starter/ui/ClusterSupport.java

@@ -51,13 +51,6 @@ public class ClusterSupport implements VaadinServiceInitListener {
 
     private String appVersion;
 
-    /**
-     * Get the current instance of the ClusterSupport.
-     */
-    public static ClusterSupport getCurrent() {
-        return CurrentInstance.get(ClusterSupport.class);
-    }
-
     /**
      * Register the global version switch listener. If set to <code>null</code>
      * the current session and the sticky cluster cookie are removed without any
@@ -82,24 +75,20 @@ public void serviceInit(ServiceInitEvent serviceInitEvent) {
                 "ClusterSupport service initialized. Registering RequestHandler with Application Version: "
                         + appVersion);
 
-        // Set the thread local instance
-        CurrentInstance.set(ClusterSupport.class, this);
-
         // Register a generic request handler for all the requests
         serviceInitEvent.addRequestHandler(this::handleRequest);
     }
 
     private boolean handleRequest(VaadinSession vaadinSession,
             VaadinRequest vaadinRequest, VaadinResponse vaadinResponse) {
+        String versionHeader = vaadinRequest
+                .getHeader(UPDATE_VERSION_HEADER);
 
         vaadinSession.access(() -> {
-            // Always check for the update version header
-            String versionHeader = vaadinRequest
-                    .getHeader(UPDATE_VERSION_HEADER);
 
+            // Always check for the update version header
+            WrappedSession session = vaadinSession.getSession();
             vaadinSession.getUIs().forEach(ui -> {
-                WrappedSession session = VaadinRequest.getCurrent()
-                        .getWrappedSession();
                 Optional<Component> versionNotifier = ui.getChildren()
                         .filter(child -> (child instanceof VersionNotifier))
                         .findFirst();

kubernetes-kit-starter/src/test/java/com/vaadin/kubernetes/starter/ui/ClusterSupportTest.java

@@ -4,8 +4,10 @@
 import java.util.Collections;
 import java.util.stream.Stream;
 
+import org.junit.Ignore;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -84,16 +86,6 @@ void tearDown() {
         vaadinResponseMockedStatic.close();
     }
 
-    @Test
-    void serviceInit_clusterSupportIsSetInCurrentInstance() {
-        ServiceInitEvent serviceInitEvent = mock(ServiceInitEvent.class);
-
-        clusterSupport.serviceInit(serviceInitEvent);
-
-        currentInstanceMockedStatic
-                .verify(() -> CurrentInstance.set(any(), any()));
-    }
-
     @Test
     void serviceInit_requestHandlerIsAdded() {
         ServiceInitEvent serviceInitEvent = mock(ServiceInitEvent.class);
@@ -122,10 +114,10 @@ void handleRequest_versionNotifierIsRemoved_ifAlreadyPresent_And_VersionHeaderIs
 
         when(vaadinRequest.getHeader(ClusterSupport.UPDATE_VERSION_HEADER))
                 .thenReturn(null);
-        when(vaadinRequest.getWrappedSession()).thenReturn(wrappedSession);
         vaadinRequestMockedStatic.when(VaadinRequest::getCurrent)
                 .thenReturn(vaadinRequest);
         when(vaadinSession.getUIs()).thenReturn(Collections.singletonList(ui));
+        when(vaadinSession.getSession()).thenReturn(wrappedSession);
         when(ui.getChildren()).thenReturn(Stream.of(versionNotifier));
 
         clusterSupport.serviceInit(serviceInitEvent);
@@ -148,7 +140,7 @@ void handleRequest_versionNotifierIsRemoved_ifAlreadyPresent_And_VersionHeaderIs
 
         when(vaadinRequest.getHeader(ClusterSupport.UPDATE_VERSION_HEADER))
                 .thenReturn("");
-        when(vaadinRequest.getWrappedSession()).thenReturn(wrappedSession);
+        when(vaadinSession.getSession()).thenReturn(wrappedSession);
         vaadinRequestMockedStatic.when(VaadinRequest::getCurrent)
                 .thenReturn(vaadinRequest);
         when(vaadinSession.getUIs()).thenReturn(Collections.singletonList(ui));
@@ -174,7 +166,7 @@ void handleRequest_versionNotifierIsRemoved_ifAlreadyPresent_And_VersionHeaderEq
 
         when(vaadinRequest.getHeader(ClusterSupport.UPDATE_VERSION_HEADER))
                 .thenReturn("1.0.0");
-        when(vaadinRequest.getWrappedSession()).thenReturn(wrappedSession);
+        when(vaadinSession.getSession()).thenReturn(wrappedSession);
         vaadinRequestMockedStatic.when(VaadinRequest::getCurrent)
                 .thenReturn(vaadinRequest);
         when(vaadinSession.getUIs()).thenReturn(Collections.singletonList(ui));
@@ -200,7 +192,7 @@ void handleRequest_versionNotifierIsNotRemoved_ifAlreadyPresent_And_VersionHeade
 
         when(vaadinRequest.getHeader(ClusterSupport.UPDATE_VERSION_HEADER))
                 .thenReturn("2.0.0");
-        when(vaadinRequest.getWrappedSession()).thenReturn(wrappedSession);
+        when(vaadinSession.getSession()).thenReturn(wrappedSession);
         vaadinRequestMockedStatic.when(VaadinRequest::getCurrent)
                 .thenReturn(vaadinRequest);
         when(vaadinSession.getUIs()).thenReturn(Collections.singletonList(ui));
@@ -225,7 +217,7 @@ void handleRequest_versionNotifierIsAdded_ifNotPresent_And_VersionHeaderEqualsAp
 
         when(vaadinRequest.getHeader(ClusterSupport.UPDATE_VERSION_HEADER))
                 .thenReturn("2.0.0");
-        when(vaadinRequest.getWrappedSession()).thenReturn(wrappedSession);
+        when(vaadinSession.getSession()).thenReturn(wrappedSession);
         vaadinRequestMockedStatic.when(VaadinRequest::getCurrent)
                 .thenReturn(vaadinRequest);
         when(vaadinSession.getUIs()).thenReturn(Collections.singletonList(ui));
@@ -243,7 +235,7 @@ void handleRequest_versionNotifierIsAdded_ifNotPresent_And_VersionHeaderEqualsAp
     }
 
     @ParameterizedTest(name = "{index} And_IfNodeSwitchIs_{0}_doAppCleanupIsCalled_{1}_times")
-    @CsvSource({ "true, 1, 1, 2, 1", "false, 0, 0, 1, 0" })
+    @CsvSource({ "true, 1, 1, 1, 1", "false, 0, 0, 0, 0" })
     void onComponentEvent_removesStickyClusterCookieAndInvalidatesSession(
             boolean nodeSwitch, int doAppCleanupTimes, int addCookieTimes,
             int getWrappedSessionTimes, int invalidateTimes)
@@ -257,11 +249,12 @@ void onComponentEvent_removesStickyClusterCookieAndInvalidatesSession(
 
         when(vaadinRequest.getHeader(ClusterSupport.UPDATE_VERSION_HEADER))
                 .thenReturn("2.0.0");
-        when(vaadinRequest.getWrappedSession()).thenReturn(wrappedSession);
         vaadinRequestMockedStatic.when(VaadinRequest::getCurrent)
                 .thenReturn(vaadinRequest);
         vaadinResponseMockedStatic.when(VaadinResponse::getCurrent)
                 .thenReturn(vaadinResponse);
+        when(vaadinRequest.getWrappedSession()).thenReturn(wrappedSession);
+        when(vaadinSession.getSession()).thenReturn(wrappedSession);
         when(vaadinSession.getUIs()).thenReturn(Collections.singletonList(ui));
         when(ui.getChildren()).thenReturn(Stream.empty());
         when(switchVersionListener.nodeSwitch(any(), any()))