Fix ApplicationListenerMethodAdapter#supportsEventType check

This commit fixes the check by avoiding a fallback to eventType's
hasUnresolvableGenerics(). This could previously lead to checking a
generic event type `A<T>` against a listener which accepts unrelated
`B` and return `true` despite the inconsistency.

Note that this wouldn't necessarily surface to the user because there is
a `catch (ClassCastException e)` down the line, which was primarily put
in place to deal with lambda-based listeners but happens to catch an
exception thrown due to the bad result of `supportsEventType`.

The `supportsEventType` now matches generic `PayloadApplicationEvent`
types with a raw counterpart, using the above fallback only in that case
and otherwise ultimately returning `false`.

Closes gh-30399

Author: simonbasle

spring-context/src/main/java/org/springframework/context/event/ApplicationListenerMethodAdapter.java

@@ -173,12 +173,12 @@ public boolean supportsEventType(ResolvableType eventType) {
 			}
 			if (PayloadApplicationEvent.class.isAssignableFrom(eventType.toClass())) {
 				ResolvableType payloadType = eventType.as(PayloadApplicationEvent.class).getGeneric();
-				if (declaredEventType.isAssignableFrom(payloadType)) {
+				if (declaredEventType.isAssignableFrom(payloadType) || eventType.hasUnresolvableGenerics()) {
 					return true;
 				}
 			}
 		}
-		return eventType.hasUnresolvableGenerics();
+		return false;
 	}
 
 	@Override

spring-context/src/test/java/org/springframework/context/event/ApplicationListenerMethodAdapterTests.java

@@ -19,6 +19,7 @@
 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.lang.reflect.UndeclaredThrowableException;
+import java.util.List;
 
 import org.junit.jupiter.api.Test;
 
@@ -325,6 +326,77 @@ public void beanInstanceRetrievedAtEveryInvocation() {
 		verify(this.context, times(2)).getBean("testBean");
 	}
 
+	// see https://github.com/spring-projects/spring-framework/issues/30399
+	@Test
+	void simplePayloadDoesNotSupportArbitraryGenericEventType() throws Exception {
+		var method = SampleEvents.class.getDeclaredMethod("handleString", String.class);
+		var adapter = new ApplicationListenerMethodAdapter(null, ApplicationListenerMethodAdapterTests.class, method);
+
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(EntityWrapper.class, Integer.class)))
+				.as("handleString(String) with EntityWrapper<Integer>").isFalse();
+		assertThat(adapter.supportsEventType(ResolvableType.forClass(EntityWrapper.class)))
+				.as("handleString(String) with EntityWrapper<?>").isFalse();
+		assertThat(adapter.supportsEventType(ResolvableType.forClass(String.class)))
+				.as("handleString(String) with String").isTrue();
+	}
+
+	// see https://github.com/spring-projects/spring-framework/issues/30399
+	@Test
+	void genericPayloadDoesNotSupportArbitraryGenericEventType() throws Exception {
+		var method = SampleEvents.class.getDeclaredMethod("handleGenericStringPayload", EntityWrapper.class);
+		var adapter = new ApplicationListenerMethodAdapter(null, ApplicationListenerMethodAdapterTests.class, method);
+
+		assertThat(adapter.supportsEventType(ResolvableType.forClass(EntityWrapper.class)))
+				.as("handleGenericStringPayload(EntityWrapper<String>) with EntityWrapper<?>").isFalse();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(EntityWrapper.class, Integer.class)))
+				.as("handleGenericStringPayload(EntityWrapper<String>) with EntityWrapper<Integer>").isFalse();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(EntityWrapper.class, String.class)))
+				.as("handleGenericStringPayload(EntityWrapper<String>) with EntityWrapper<String>").isTrue();
+	}
+
+	// see https://github.com/spring-projects/spring-framework/issues/30399
+	@Test
+	void rawGenericPayloadDoesNotSupportArbitraryGenericEventType() throws Exception {
+		var method = SampleEvents.class.getDeclaredMethod("handleGenericAnyPayload", EntityWrapper.class);
+		var adapter = new ApplicationListenerMethodAdapter(null, ApplicationListenerMethodAdapterTests.class, method);
+
+		assertThat(adapter.supportsEventType(ResolvableType.forClass(EntityWrapper.class)))
+				.as("handleGenericAnyPayload(EntityWrapper<?>) with EntityWrapper<?>").isTrue();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(EntityWrapper.class, Integer.class)))
+				.as("handleGenericAnyPayload(EntityWrapper<?>) with EntityWrapper<Integer>").isTrue();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(EntityWrapper.class, String.class)))
+				.as("handleGenericAnyPayload(EntityWrapper<?>) with EntityWrapper<String>").isTrue();
+		assertThat(adapter.supportsEventType(ResolvableType.forClass(List.class)))
+				.as("handleGenericAnyPayload(EntityWrapper<?>) with List<?>").isFalse();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(List.class, String.class)))
+				.as("handleGenericAnyPayload(EntityWrapper<?>) with List<String>").isFalse();
+	}
+
+	@Test
+	void genericApplicationEventSupportsSpecificType() throws Exception {
+		var method = SampleEvents.class.getDeclaredMethod("handleGenericString", GenericTestEvent.class);
+		var adapter = new ApplicationListenerMethodAdapter(null, ApplicationListenerMethodAdapterTests.class, method);
+
+		assertThat(adapter.supportsEventType(ResolvableType.forClass(GenericTestEvent.class)))
+				.as("handleGenericString(GenericTestEvent<String>) with GenericTestEvent<?>").isFalse();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(GenericTestEvent.class, Integer.class)))
+				.as("handleGenericString(GenericTestEvent<String>) with GenericTestEvent<Integer>").isFalse();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(GenericTestEvent.class, String.class)))
+				.as("handleGenericString(GenericTestEvent<String>) with GenericTestEvent<String>").isTrue();
+	}
+
+	@Test
+	void genericRawApplicationEventSupportsRawTypeAndAnySpecificType() throws Exception {
+		var method = SampleEvents.class.getDeclaredMethod("handleGenericRaw", GenericTestEvent.class);
+		var adapter = new ApplicationListenerMethodAdapter(null, ApplicationListenerMethodAdapterTests.class, method);
+
+		assertThat(adapter.supportsEventType(ResolvableType.forClass(GenericTestEvent.class)))
+				.as("handleGenericRaw(GenericTestEvent<?>) with GenericTestEvent<?>").isTrue();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(GenericTestEvent.class, String.class)))
+				.as("handleGenericRaw(GenericTestEvent<?>) with GenericTestEvent<String>").isTrue();
+		assertThat(adapter.supportsEventType(ResolvableType.forClassWithGenerics(GenericTestEvent.class, Integer.class)))
+				.as("handleGenericRaw(GenericTestEvent<?>) with GenericTestEvent<Integer>").isTrue();
+	}
 
 	private void supportsEventType(boolean match, Method method, ResolvableType eventType) {
 		ApplicationListenerMethodAdapter adapter = createTestInstance(method);
@@ -373,6 +445,10 @@ public void handleRaw(ApplicationEvent event) {
 		public void handleGenericString(GenericTestEvent<String> event) {
 		}
 
+		@EventListener
+		public void handleGenericRaw(GenericTestEvent<?> event) {
+		}
+
 		@EventListener
 		public void handleString(String payload) {
 		}