Merge branch '2.1.x' into 2.2.x

Closes gh-21070

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration.java

@@ -402,6 +402,7 @@ public class WebMvcAutoConfiguration {
 					new TemplateAvailabilityProviders(applicationContext), applicationContext, getWelcomePage(),
 					this.mvcProperties.getStaticPathPattern());
 			welcomePageHandlerMapping.setInterceptors(getInterceptors(mvcConversionService, mvcResourceUrlProvider));
+			welcomePageHandlerMapping.setCorsConfigurations(getCorsConfigurations());
 			return welcomePageHandlerMapping;
 		}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfigurationTests.java

@@ -76,6 +76,7 @@ import org.springframework.web.accept.ParameterContentNegotiationStrategy;
 import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
 import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
 import org.springframework.web.context.request.ServletWebRequest;
+import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
 import org.springframework.web.filter.FormContentFilter;
 import org.springframework.web.filter.HiddenHttpMethodFilter;
 import org.springframework.web.filter.RequestContextFilter;
@@ -87,6 +88,7 @@ import org.springframework.web.servlet.View;
 import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.config.annotation.AsyncSupportConfigurer;
 import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;
+import org.springframework.web.servlet.config.annotation.CorsRegistry;
 import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 import org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver;
@@ -536,7 +538,19 @@ class WebMvcAutoConfigurationTests {
 		this.contextRunner.withPropertyValues("spring.resources.static-locations:classpath:/welcome-page/")
 				.run((context) -> {
 					assertThat(context).hasSingleBean(WelcomePageHandlerMapping.class);
-					assertThat(context.getBean(WelcomePageHandlerMapping.class).getRootHandler()).isNotNull();
+					WelcomePageHandlerMapping bean = context.getBean(WelcomePageHandlerMapping.class);
+					assertThat(bean.getRootHandler()).isNotNull();
+				});
+	}
+
+	@Test
+	void welcomePageHandlerIncludesCorsConfiguration() {
+		this.contextRunner.withPropertyValues("spring.resources.static-locations:classpath:/welcome-page/")
+				.withUserConfiguration(CorsConfigurer.class).run((context) -> {
+					WelcomePageHandlerMapping bean = context.getBean(WelcomePageHandlerMapping.class);
+					UrlBasedCorsConfigurationSource source = (UrlBasedCorsConfigurationSource) ReflectionTestUtils
+							.getField(bean, "corsConfigurationSource");
+					assertThat(source.getCorsConfigurations()).containsKey("/**");
 				});
 	}
 
@@ -1157,4 +1171,14 @@ class WebMvcAutoConfigurationTests {
 
 	}
 
+	@Configuration
+	static class CorsConfigurer implements WebMvcConfigurer {
+
+		@Override
+		public void addCorsMappings(CorsRegistry registry) {
+			registry.addMapping("/**").allowedMethods("GET");
+		}
+
+	}
+
 }