Ensure @Component scanned from jar on classpath can be inspected

And test it using a new POF sample.

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

@@ -59,7 +59,7 @@ import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
-import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.io.Resource;
 import org.springframework.core.type.StandardMethodMetadata;
 import org.springframework.core.type.classreading.MethodMetadataReadingVisitor;
 import org.springframework.messaging.Message;
@@ -407,7 +407,13 @@ public class ContextFunctionCatalogAutoConfiguration {
 						.getIntrospectedMethod().getGenericReturnType();
 				param = extractType(type, paramType, index);
 			}
-			else if (source instanceof FileSystemResource) {
+			else if (source instanceof MethodMetadataReadingVisitor) {
+				// A component scan with @Beans
+				MethodMetadataReadingVisitor visitor = (MethodMetadataReadingVisitor) source;
+				Type type = findBeanType(definition, visitor);
+				param = extractType(type, paramType, index);
+			}
+			else if (source instanceof Resource) {
 				try {
 					Class<?> beanType = ClassUtils.forName(definition.getBeanClassName(),
 							null);
@@ -427,12 +433,6 @@ public class ContextFunctionCatalogAutoConfiguration {
 							"Cannot instrospect bean: " + definition, e);
 				}
 			}
-			else if (source instanceof MethodMetadataReadingVisitor) {
-				// A component scan with @Beans
-				MethodMetadataReadingVisitor visitor = (MethodMetadataReadingVisitor) source;
-				Type type = findBeanType(definition, visitor);
-				param = extractType(type, paramType, index);
-			}
 			else {
 				ResolvableType resolvable = (ResolvableType) getField(definition,
 						"targetType");

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

@@ -16,6 +16,8 @@
 
 package org.springframework.cloud.function.context;
 
+import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -39,9 +41,12 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.FileSystemResource;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StreamUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -139,6 +144,33 @@ public class ContextFunctionCatalogAutoConfigurationTests {
 		assertThat(inspector.getInputWrapper("function")).isAssignableFrom(Map.class);
 	}
 
+	@Test
+	public void componentScanJarFunction() {
+		try {
+			create("greeter.jar", ComponentScanJarConfiguration.class);
+			assertThat(context.getBean("greeter")).isInstanceOf(Function.class);
+			assertThat(catalog.lookupFunction("greeter")).isInstanceOf(Function.class);
+			assertThat(inspector.getInputType("greeter")).isAssignableFrom(String.class);
+			assertThat(inspector.getInputWrapper("greeter"))
+					.isAssignableFrom(String.class);
+		}
+		finally {
+			ClassUtils.overrideThreadContextClassLoader(getClass().getClassLoader());
+		}
+	}
+
+	private void create(String jarfile, Class<?> config, String... props) {
+		try {
+			URL[] urls = new URL[] { new ClassPathResource(jarfile).getURL() };
+			ClassUtils.overrideThreadContextClassLoader(
+					new URLClassLoader(urls, getClass().getClassLoader()));
+			create(config, props);
+		}
+		catch (Exception e) {
+			ReflectionUtils.rethrowRuntimeException(e);
+		}
+	}
+
 	@Test
 	public void simpleSupplier() {
 		create(SimpleConfiguration.class);
@@ -304,6 +336,12 @@ public class ContextFunctionCatalogAutoConfigurationTests {
 	protected static class ComponentScanConfiguration {
 	}
 
+	@EnableAutoConfiguration
+	@Configuration
+	@FunctionScan
+	protected static class ComponentScanJarConfiguration {
+	}
+
 	@EnableAutoConfiguration
 	@Configuration
 	protected static class GenericFluxConfiguration {