Merge branch 'gh-3943'

spring-boot/src/main/java/org/springframework/boot/web/servlet/ServletComponentScanRegistrar.java

@@ -57,12 +57,11 @@ class ServletComponentScanRegistrar implements ImportBeanDefinitionRegistrar {
 			Set<String> packagesToScan) {
 		BeanDefinition definition = registry.getBeanDefinition(BEAN_NAME);
 		ValueHolder constructorArguments = definition.getConstructorArgumentValues()
-				.getGenericArgumentValue(String[].class);
+				.getGenericArgumentValue(Set.class);
 		@SuppressWarnings("unchecked")
-		Set<String> mergedPackages = new LinkedHashSet<String>(
+		Set<String> mergedPackages = (Set<String>) constructorArguments.getValue();
-				(Set<String>) constructorArguments.getValue());
 		mergedPackages.addAll(packagesToScan);
-		constructorArguments.setValue(packagesToScan);
+		constructorArguments.setValue(mergedPackages);
 	}
 
 	private void addPostProcessor(BeanDefinitionRegistry registry,

spring-boot/src/test/java/org/springframework/boot/web/servlet/ServletComponentScanRegistrarTests.java

@@ -84,6 +84,18 @@ public class ServletComponentScanRegistrarTests {
 				.getPackage().getName()));
 	}
 
+	@Test
+	public void packagesFromMultipleAnnotationsAreMerged() {
+		this.context = new AnnotationConfigApplicationContext(BasePackages.class,
+				AdditionalPackages.class);
+		ServletComponentRegisteringPostProcessor postProcessor = this.context
+				.getBean(ServletComponentRegisteringPostProcessor.class);
+		assertThat(
+				postProcessor.getPackagesToScan(),
+				containsInAnyOrder("com.example.foo", "com.example.bar",
+						"com.example.baz"));
+	}
+
 	@Configuration
 	@ServletComponentScan({ "com.example.foo", "com.example.bar" })
 	static class ValuePackages {
@@ -96,6 +108,12 @@ public class ServletComponentScanRegistrarTests {
 
 	}
 
+	@Configuration
+	@ServletComponentScan(basePackages = "com.example.baz")
+	static class AdditionalPackages {
+
+	}
+
 	@Configuration
 	@ServletComponentScan(basePackageClasses = ServletComponentScanRegistrarTests.class)
 	static class BasePackageClasses {