From c4dfffe0bac5b0d6924d0a868d5757c3c32debee Mon Sep 17 00:00:00 2001
From: Oleg Zhurakousky <ozhurakousky@vmware.com>
Date: Fri, 5 Feb 2021 16:03:45 +0100
Subject: [PATCH] GH-640 Fix NPE with non-Message json conversion

Resolves #640

Added test
---
 .../catalog/SimpleFunctionRegistry.java       |  6 ++---
 .../catalog/SimpleFunctionRegistryTests.java  | 24 +++++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
index 184f3a569..7ec7ced57 100644
--- a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
+++ b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
@@ -1001,10 +1001,10 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 					&& SimpleFunctionRegistry.this.conversionService.canConvert(input.getClass(), rawInputType)) {
 				convertedInput = SimpleFunctionRegistry.this.conversionService.convert(input, rawInputType);
 			}
-			if (convertedInput == null && input.getClass().isAssignableFrom(rawInputType)) {
-				convertedInput = input;
+			if (convertedInput == null && logger.isDebugEnabled()) {
+				logger.debug("Failed to convert input '" + input + "' to type " + inputType + ". Will use it as is.");
 			}
-			return convertedInput;
+			return convertedInput == null ? input : convertedInput;
 		}
 
 		/*
diff --git a/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistryTests.java b/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistryTests.java
index 08ab41934..4dc8451d6 100644
--- a/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistryTests.java
+++ b/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistryTests.java
@@ -86,6 +86,21 @@ public class SimpleFunctionRegistryTests {
 		this.conversionService = new DefaultConversionService();
 	}
 
+	@Test
+	public void testSCF640() {
+		Echo function = new Echo();
+		FunctionRegistration<Echo> registration = new FunctionRegistration<>(
+				function, "echo").type(FunctionType.of(Echo.class));
+		SimpleFunctionRegistry catalog = new SimpleFunctionRegistry(this.conversionService, this.messageConverter,
+				new JacksonMapper(new ObjectMapper()));
+		catalog.register(registration);
+
+		FunctionInvocationWrapper lookedUpFunction = catalog.lookup("echo");
+		Object result = lookedUpFunction.apply("{\"HELLO\":\"WORLD\"}");
+		assertThat(result).isNotInstanceOf(Message.class);
+		assertThat(result).isEqualTo("{\"HELLO\":\"WORLD\"}");
+	}
+
 	@SuppressWarnings("unchecked")
 	@Test
 	public void testSCF588() {
@@ -468,6 +483,15 @@ public class SimpleFunctionRegistryTests {
 
 	}
 
+	private static class Echo implements Function<Object, Object> {
+
+		@Override
+		public Object apply(Object t) {
+			return t;
+		}
+
+	}
+
 	private static class UpperCaseMessage
 			implements Function<Message<String>, Message<String>> {