fix: ensure requestEnd clears Vaadin thread locals (#20687) (#20693)

Makes sure that Vaadin thread locals are cleared even if something
fails durung requestEnd execution. It also wraps Vaadin interceptors
execution in a try/catch block to ensure all of them are invoked
and that potential failures does not affect the continuation of
requestEnd method.

flow-server/src/main/java/com/vaadin/flow/server/VaadinService.java

@@ -1466,19 +1466,23 @@ public void requestStart(VaadinRequest request, VaadinResponse response) {
      */
     public void requestEnd(VaadinRequest request, VaadinResponse response,
             VaadinSession session) {
-        if (session != null) {
-            assert VaadinSession.getCurrent() == session;
-            session.lock();
-            try {
-                cleanupSession(session);
-                final long duration = (System.nanoTime() - (Long) request
-                        .getAttribute(REQUEST_START_TIME_ATTRIBUTE)) / 1000000;
-                session.setLastRequestDuration(duration);
-            } finally {
-                session.unlock();
+        try {
+            if (session != null) {
+                assert VaadinSession.getCurrent() == session;
+                session.lock();
+                try {
+                    cleanupSession(session);
+                    final long duration = (System.nanoTime() - (Long) request
+                            .getAttribute(REQUEST_START_TIME_ATTRIBUTE))
+                            / 1000000;
+                    session.setLastRequestDuration(duration);
+                } finally {
+                    session.unlock();
+                }
             }
+        } finally {
+            CurrentInstance.clearAll();
         }
-        CurrentInstance.clearAll();
     }
 
     /**

flow-server/src/test/java/com/vaadin/flow/server/VaadinServiceTest.java

@@ -78,6 +78,44 @@ private String createCriticalNotification(String caption, String message,
                 details, url);
     }
 
+    @Test
+    public void requestEnd_serviceFailure_threadLocalsCleared() {
+        MockVaadinServletService service = new MockVaadinServletService() {
+            @Override
+            void cleanupSession(VaadinSession session) {
+                throw new RuntimeException("BOOM");
+            }
+        };
+        service.init();
+
+        VaadinRequest request = Mockito.mock(VaadinRequest.class);
+        VaadinResponse response = Mockito.mock(VaadinResponse.class);
+        service.requestStart(request, response);
+
+        Assert.assertSame(service, VaadinService.getCurrent());
+        Assert.assertSame(request, VaadinRequest.getCurrent());
+        Assert.assertSame(response, VaadinResponse.getCurrent());
+
+        VaadinSession session = Mockito.mock(VaadinSession.class);
+        VaadinSession.setCurrent(session);
+
+        try {
+            service.requestEnd(request, response, session);
+            Assert.fail("Should have thrown an exception");
+        } catch (Exception e) {
+            Assert.assertNull("VaadinService.current",
+                    VaadinService.getCurrent());
+            Assert.assertNull("VaadinSession.current",
+                    VaadinSession.getCurrent());
+            Assert.assertNull("VaadinRequest.current",
+                    VaadinRequest.getCurrent());
+            Assert.assertNull("VaadinResponse.current",
+                    VaadinResponse.getCurrent());
+        } finally {
+            CurrentInstance.clearAll();
+        }
+    }
+
     @Test
     public void testFireSessionDestroy()
             throws ServletException, ServiceException {