Fix #500. Implement checking of views to prevent injection of scopes

mvvmfx/src/main/java/de/saxsys/mvvmfx/internal/viewloader/FxmlViewLoader.java

@@ -363,6 +363,8 @@ public Object call(Class<?> type) {
     }
 
     private static void handleInjection(View codeBehind, ResourceBundle resourceBundle, ContextImpl context, ObservableBooleanValue viewInSceneProperty) {
+        ViewLoaderReflectionUtils.checkScopesInView(codeBehind);
+
         ResourceBundleInjector.injectResourceBundle(codeBehind, resourceBundle);
 
         Consumer<ViewModel> newVmConsumer = viewModel -> {
@@ -379,6 +381,8 @@ private static void handleInjection(View codeBehind, ResourceBundle resourceBund
 
     private static void handleInjection(View codeBehind, ResourceBundle resourceBundle, ViewModel viewModel,
             ContextImpl context, ObservableBooleanValue viewInSceneProperty) {
+        ViewLoaderReflectionUtils.checkScopesInView(codeBehind);
+
         ResourceBundleInjector.injectResourceBundle(codeBehind, resourceBundle);
 
         if (viewModel != null) {

mvvmfx/src/main/java/de/saxsys/mvvmfx/internal/viewloader/ViewLoaderReflectionUtils.java

@@ -470,4 +470,20 @@ static void addSceneLifecycleHooks(ViewModel viewModel, ObservableBooleanValue v
             }
         }
     }
+
+    /**
+     * This method is used to check if the given View instance has one or more fields that try to inject a scope
+     * with the {@link InjectScope} annotation.
+     * This is a violation of the mvvm-pattern and therefore this method will throw an exception with a message describing the
+     * error.
+     */
+    static void checkScopesInView(View codeBehind) {
+        List<Field> scopeFields = ReflectionUtils.getFieldsWithAnnotation(codeBehind, InjectScope.class);
+
+        if(!scopeFields.isEmpty()) {
+            throw new IllegalStateException("The view class [" + codeBehind.getClass().getSimpleName() + "] tries to inject a Scope with " +
+                    "@InjectScope. This would be a violation of the mvvm pattern. Scopes are only supported in ViewModels.");
+        }
+
+    }
 }

mvvmfx/src/test/java/de/saxsys/mvvmfx/scopes/scope_in_view/RootView.java

@@ -0,0 +1,14 @@
+package de.saxsys.mvvmfx.scopes.scope_in_view;
+
+import de.saxsys.mvvmfx.FxmlView;
+import de.saxsys.mvvmfx.InjectViewModel;
+
+public class RootView implements FxmlView<RootViewModel> {
+
+	@InjectViewModel
+	private RootViewModel viewModel;
+
+	public void initialize() {
+
+	}
+}

mvvmfx/src/test/java/de/saxsys/mvvmfx/scopes/scope_in_view/RootViewModel.java

@@ -0,0 +1,7 @@
+package de.saxsys.mvvmfx.scopes.scope_in_view;
+
+import de.saxsys.mvvmfx.ViewModel;
+
+public class RootViewModel implements ViewModel {
+
+}

mvvmfx/src/test/java/de/saxsys/mvvmfx/scopes/scope_in_view/ScopeInViewTest.java

@@ -0,0 +1,60 @@
+package de.saxsys.mvvmfx.scopes.scope_in_view;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+import de.saxsys.mvvmfx.FluentViewLoader;
+import de.saxsys.mvvmfx.testingutils.ExceptionUtils;
+
+/**
+ * Scopes are only allowed in ViewModels. If a user tries to inject them in a View/CodeBehind then
+ * an exception should be thrown to notify the user about this error.
+ */
+public class ScopeInViewTest {
+
+	@Test
+	public void testDirectLoading() {
+		RuntimeException runtimeException = assertThrows(RuntimeException.class, () -> {
+			FluentViewLoader.fxmlView(ScopeInViewTestView.class)
+					.providedScopes(new TestScope())
+					.load();
+		});
+
+		Throwable rootCause = ExceptionUtils.getRootCause(runtimeException);
+		assertThat(rootCause).isInstanceOf(IllegalStateException.class).hasMessageContaining("tries to inject a Scope");
+	}
+
+	/**
+	 * This test case reproduces a separate branch in the viewloader logic that is used when
+	 * a viewModel and a view instance is provided.
+	 */
+	@Test
+	public void testDirectLoadingWithExistingViewModel() {
+		RuntimeException runtimeException = assertThrows(RuntimeException.class, () -> {
+			FluentViewLoader.fxmlView(ScopeInViewTestView.class)
+					.providedScopes(new TestScope())
+					.codeBehind(new ScopeInViewTestView())
+					.viewModel(new ScopeInViewTestViewModel())
+					.load();
+		});
+
+		Throwable rootCause = ExceptionUtils.getRootCause(runtimeException);
+		assertThat(rootCause).isInstanceOf(IllegalStateException.class).hasMessageContaining("tries to inject a Scope");
+	}
+
+
+	@Test
+	public void testSubviewLoading() {
+		RuntimeException runtimeException = assertThrows(RuntimeException.class, () -> {
+			FluentViewLoader.fxmlView(RootView.class)
+					.providedScopes(new TestScope())
+					.load();
+		});
+
+
+		Throwable rootCause = ExceptionUtils.getRootCause(runtimeException);
+		assertThat(rootCause).isInstanceOf(IllegalStateException.class).hasMessageContaining("tries to inject a Scope");
+	}
+}

mvvmfx/src/test/java/de/saxsys/mvvmfx/scopes/scope_in_view/ScopeInViewTestView.java

@@ -0,0 +1,18 @@
+package de.saxsys.mvvmfx.scopes.scope_in_view;
+
+import de.saxsys.mvvmfx.FxmlView;
+import de.saxsys.mvvmfx.InjectScope;
+import de.saxsys.mvvmfx.InjectViewModel;
+
+public class ScopeInViewTestView implements FxmlView<ScopeInViewTestViewModel> {
+
+	@InjectScope
+	private TestScope scope;
+
+	@InjectViewModel
+	private ScopeInViewTestViewModel viewModel;
+
+	public void initialize() {
+
+	}
+}

mvvmfx/src/test/java/de/saxsys/mvvmfx/scopes/scope_in_view/ScopeInViewTestViewModel.java

@@ -0,0 +1,8 @@
+package de.saxsys.mvvmfx.scopes.scope_in_view;
+
+import de.saxsys.mvvmfx.ScopeProvider;
+import de.saxsys.mvvmfx.ViewModel;
+
+public class ScopeInViewTestViewModel implements ViewModel {
+
+}

mvvmfx/src/test/java/de/saxsys/mvvmfx/scopes/scope_in_view/TestScope.java

@@ -0,0 +1,7 @@
+package de.saxsys.mvvmfx.scopes.scope_in_view;
+
+import de.saxsys.mvvmfx.Scope;
+
+public class TestScope implements Scope {
+
+}

mvvmfx/src/test/resources/de/saxsys/mvvmfx/scopes/scope_in_view/RootView.fxml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.layout.AnchorPane?>
+
+
+<AnchorPane fx:controller="de.saxsys.mvvmfx.scopes.scope_in_view.RootView" xmlns="http://javafx.com/javafx/8.0.60"
+            xmlns:fx="http://javafx.com/fxml/1">
+    <fx:include source="ScopeInViewTestView.fxml"/>
+</AnchorPane>

mvvmfx/src/test/resources/de/saxsys/mvvmfx/scopes/scope_in_view/ScopeInViewTestView.fxml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.layout.AnchorPane?>
+
+
+<AnchorPane fx:controller="de.saxsys.mvvmfx.scopes.scope_in_view.ScopeInViewTestView" xmlns="http://javafx.com/javafx/8.0.60"
+            xmlns:fx="http://javafx.com/fxml/1">
+</AnchorPane>