#18012 feat!: reject AppShells classes which extend Components. Fixes #…

…18012
vaadin · Nov 30, 2023 · eaad7a9 · eaad7a9
1 parent 738ec7c
commit eaad7a9
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diff --git a/flow-server/src/main/java/com/vaadin/flow/server/AppShellRegistry.java b/flow-server/src/main/java/com/vaadin/flow/server/AppShellRegistry.java
@@ -22,6 +22,7 @@
 import java.util.List;
 import java.util.function.Consumer;
 
+import com.vaadin.flow.component.Component;
 import org.jsoup.nodes.Document;
 import org.jsoup.nodes.Element;
 
@@ -62,6 +63,9 @@ public class AppShellRegistry implements Serializable {
 
     private static final String ERROR_MULTIPLE_ANNOTATION = "%n%s is not a repeatable annotation type.%n";
 
+    private static final String ERROR_EXTENDS_COMPONENT = "%nApp shell class is not allowed to extend Vaadin Component: %s. "
+            + "App shells are intended for page configuration and are instantiated before the UI is created.%n";
+
     // There must be no more than one of the following elements per document
     private static final String[] UNIQUE_ELEMENTS = { "meta[name=viewport]",
             "meta[name=description]", "title", "base" };
@@ -134,6 +138,10 @@ public void setShell(Class<? extends AppShellConfigurator> shell) {
                     String.format(AppShellRegistry.ERROR_MULTIPLE_SHELL,
                             this.appShellClass.getName(), shell.getName()));
         }
+        if (shell != null && Component.class.isAssignableFrom(shell)) {
+            throw new InvalidApplicationConfigurationException(
+                    String.format(ERROR_EXTENDS_COMPONENT, shell.getName()));
+        }
         this.appShellClass = shell;
     }
 

diff --git a/flow-server/src/test/java/com/vaadin/flow/server/startup/VaadinAppShellInitializerTest.java b/flow-server/src/test/java/com/vaadin/flow/server/startup/VaadinAppShellInitializerTest.java
@@ -15,6 +15,7 @@
 import java.util.Set;
 import java.util.concurrent.ConcurrentMap;
 
+import com.vaadin.flow.component.Tag;
 import org.jsoup.nodes.Document;
 import org.jsoup.nodes.Element;
 import org.junit.After;
@@ -174,6 +175,11 @@ public static class OffendingNonPwaClass {
     public static class AppShellWithPWA implements AppShellConfigurator {
     }
 
+    @Tag("div")
+    public static class AppShellExtendingComponent extends Component
+            implements AppShellConfigurator {
+    }
+
     @Rule
     public ExpectedException exception = ExpectedException.none();
 
@@ -439,6 +445,13 @@ public void should_not_link_to_PWA_article() throws Exception {
         assertTrue(arg.getValue().contains("@Viewport"));
     }
 
+    @Test(expected = InvalidApplicationConfigurationException.class)
+    public void should_throwException_when_appShellExtendsComponent()
+            throws Exception {
+        classes.add(AppShellExtendingComponent.class);
+        initializer.process(classes, servletContext);
+    }
+
     private VaadinServletRequest createVaadinRequest(String pathInfo) {
         HttpServletRequest request = createRequest(pathInfo);
         return new VaadinServletRequest(request, service);