Fix regression for implicit composition

Also, added message check in AWS destination resolver

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/main/java/org/springframework/cloud/function/adapter/aws/LambdaDestinationResolver.java

@@ -26,10 +26,12 @@ public class LambdaDestinationResolver implements DestinationResolver {
 
 	@Override
 	public String destination(Supplier<?> supplier, String name, Object value) {
-		Message<?> message = (Message<?>) value;
+		if (value instanceof Message) {
-		MessageHeaders headers = message.getHeaders();
+			Message<?> message = (Message<?>) value;
-		if (headers.containsKey("lambda-runtime-aws-request-id")) {
+			MessageHeaders headers = message.getHeaders();
-			return (String) headers.get("lambda-runtime-aws-request-id");
+			if (headers.containsKey("lambda-runtime-aws-request-id")) {
+				return (String) headers.get("lambda-runtime-aws-request-id");
+			}
 		}
 		return "unknown";
 	}

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/BeanFactoryAwareFunctionRegistry.java

@@ -154,7 +154,7 @@ public class BeanFactoryAwareFunctionRegistry extends SimpleFunctionRegistry imp
 
 	@Override
 	String discoverDefaultDefinitionIfNecessary(String definition) {
-		if (StringUtils.isEmpty(definition)) {
+		if (StringUtils.isEmpty(definition) || definition.endsWith("|")) {
 			// the underscores are for Kotlin function registrations (see KotlinLambdaToFunctionAutoConfiguration)
 			String[] functionNames = Stream.of(this.applicationContext.getBeanNamesForType(Function.class))
 				.filter(n -> !n.endsWith(FunctionRegistration.REGISTRATION_NAME_SUFFIX) && !n
@@ -184,6 +184,10 @@ public class BeanFactoryAwareFunctionRegistry extends SimpleFunctionRegistry imp
 				}
 				definition = names.get(0);
 			}
+			else if (definition.endsWith("|")) {
+				Set<String> fNames = this.getNames(null);
+				definition = this.determinImpliedDefinition(fNames, definition);
+			}
 			else {
 				definition = this.discoverDefaultDefinitionFromRegistration();
 			}

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/InMemoryFunctionCatalog.java

@@ -27,7 +27,10 @@ import org.springframework.util.Assert;
  * @author Dave Syer
  * @author Mark Fisher
  * @author Oleg Zhurakousky
+ *
+ * @deprecated since 3.1. End-of-life. Not used by the framework anymore in favor of SimpleFunctionRegistry
  */
+@Deprecated
 public class InMemoryFunctionCatalog extends AbstractComposableFunctionRegistry {
 
 	public InMemoryFunctionCatalog() {

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java

@@ -26,6 +26,7 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -48,6 +49,7 @@ import reactor.util.function.Tuples;
 
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.aop.support.AopUtils;
+import org.springframework.beans.factory.BeanFactory;
 import org.springframework.cloud.function.context.FunctionProperties;
 import org.springframework.cloud.function.context.FunctionRegistration;
 import org.springframework.cloud.function.context.FunctionRegistry;
@@ -72,6 +74,11 @@ import org.springframework.util.StringUtils;
 
 
 /**
+ *
+ * Basic implementation of FunctionRegistry which maintains the cache of registered functions while
+ * decorating them with additional features such as transparent type conversion, composition, routing etc.
+ *
+ * Unlike {@link BeanFactoryAwareFunctionRegistry}, this implementation does not depend on {@link BeanFactory}.
  *
  * @author Oleg Zhurakousky
  *
@@ -217,8 +224,31 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 		else if (!this.registrationsByName.containsKey(definition) && this.registrationsByName.size() == 1) {
 			definition = this.registrationsByName.keySet().iterator().next();
 		}
+		else if (definition.endsWith("|")) {
+			if (this.registrationsByName.size() == 2) {
+				Set<String> fNames = this.getNames(null);
+				definition = this.determinImpliedDefinition(fNames, definition);
+			}
+		}
 		return definition;
+	}
 
+	String determinImpliedDefinition(Set<String> fNames, String originalDefinition) {
+		if (fNames.size() == 2) {
+			Iterator<String> iter = fNames.iterator();
+			String n1 = iter.next();
+			String n2 = iter.next();
+			String[] definitionName = StringUtils.delimitedListToStringArray(originalDefinition, "|");
+			if (definitionName[0].equals(n1)) {
+				definitionName[1] = n2;
+				originalDefinition = definitionName[0] + "|" + definitionName[1];
+			}
+			else {
+				definitionName[1] = n1;
+				originalDefinition = definitionName[0] + "|" + definitionName[1];
+			}
+		}
+		return originalDefinition;
 	}
 
 	Type discovereFunctionTypeByName(String name) {

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/ContextFunctionCatalogInitializer.java

@@ -169,7 +169,6 @@ public class ContextFunctionCatalogInitializer implements ApplicationContextInit
 			}
 
 			if (this.context.getBeanFactory().getBeanNamesForType(FunctionCatalog.class, false, false).length == 0) {
-
 				this.context.registerBean(SimpleFunctionRegistry.class, () -> {
 					List<MessageConverter> messageConverters = new ArrayList<>();
 					JsonMapper jsonMapper = this.context.getBean(JsonMapper.class);

spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistryTests.java

@@ -28,6 +28,7 @@ import org.junit.Test;
 import reactor.core.publisher.Flux;
 
 import org.springframework.cloud.function.context.FunctionRegistration;
+import org.springframework.cloud.function.context.FunctionRegistry;
 import org.springframework.cloud.function.context.FunctionType;
 import org.springframework.cloud.function.context.catalog.SimpleFunctionRegistry.FunctionInvocationWrapper;
 import org.springframework.cloud.function.context.config.JsonMessageConverter;
@@ -103,21 +104,20 @@ public class SimpleFunctionRegistryTests {
 	}
 
 	@Test
-	@Ignore
 	public void testFunctionCompositionImplicit() {
 		FunctionRegistration<Words> wordsRegistration = new FunctionRegistration<>(
 				new Words(), "words").type(FunctionType.of(Words.class));
 		FunctionRegistration<Reverse> reverseRegistration = new FunctionRegistration<>(
 				new Reverse(), "reverse").type(FunctionType.of(Reverse.class));
-		SimpleFunctionRegistry catalog = new SimpleFunctionRegistry(this.conversionService, this.messageConverter);
+		FunctionRegistry catalog = new SimpleFunctionRegistry(this.conversionService, this.messageConverter);
 		catalog.register(wordsRegistration);
 		catalog.register(reverseRegistration);
 
 		// There's only one function, we should be able to leave that blank
-		Supplier<Flux<String>> lookedUpFunction = catalog.lookup("words|");
+		Supplier<String> lookedUpFunction = catalog.lookup("words|");
 
 		assertThat(lookedUpFunction).isNotNull();
-		assertThat(lookedUpFunction.get().blockFirst()).isEqualTo("olleh");
+		assertThat(lookedUpFunction.get()).isEqualTo("olleh");
 	}
 
 	@Test