Align with 5.0.x change #cd3ed7

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultRenderingResponseBuilder.java

@@ -184,7 +184,7 @@ class DefaultRenderingResponseBuilder implements RenderingResponse.Builder {
 
 		@Override
 		protected Mono<Void> writeToInternal(ServerWebExchange exchange, Context context) {
-			MediaType responseContentType = exchange.getResponse().getHeaders().getContentType();
+			MediaType contentType = exchange.getResponse().getHeaders().getContentType();
 			Locale locale = LocaleContextHolder.getLocale(exchange.getLocaleContext());
 			Stream<ViewResolver> viewResolverStream = context.viewResolvers().stream();
 
@@ -195,8 +195,9 @@ class DefaultRenderingResponseBuilder implements RenderingResponse.Builder {
 							new IllegalArgumentException("Could not resolve view with name '" + name() + "'")))
 					.flatMap(view -> {
 						List<MediaType> mediaTypes = view.getSupportedMediaTypes();
-						MediaType contentType = (responseContentType == null && !mediaTypes.isEmpty() ? mediaTypes.get(0) : responseContentType);
-						return view.render(model(), contentType, exchange);
+						return view.render(model(),
+								contentType == null && !mediaTypes.isEmpty() ? mediaTypes.get(0) : contentType,
+								exchange);
 					});
 		}
 

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageReaderArgumentResolver.java

@@ -144,6 +144,7 @@ public abstract class AbstractMessageReaderArgumentResolver extends HandlerMetho
 		Class<?> resolvedType = bodyType.resolve();
 		ReactiveAdapter adapter = (resolvedType != null ? getAdapterRegistry().getAdapter(resolvedType) : null);
 		ResolvableType elementType = (adapter != null ? bodyType.getGeneric() : bodyType);
+		isBodyRequired = isBodyRequired || (adapter != null && !adapter.supportsEmpty());
 
 		ServerHttpRequest request = exchange.getRequest();
 		ServerHttpResponse response = exchange.getResponse();
@@ -151,17 +152,14 @@ public abstract class AbstractMessageReaderArgumentResolver extends HandlerMetho
 		MediaType contentType = request.getHeaders().getContentType();
 		MediaType mediaType = (contentType != null ? contentType : MediaType.APPLICATION_OCTET_STREAM);
 
-		Supplier<Throwable> missingBodyError = isBodyRequired || (adapter != null && !adapter.supportsEmpty()) ?
-				() -> handleMissingBody(bodyParam) : null;
-
 		for (HttpMessageReader<?> reader : getMessageReaders()) {
 			if (reader.canRead(elementType, mediaType)) {
 				Map<String, Object> readHints = Collections.emptyMap();
 				if (adapter != null && adapter.isMultiValue()) {
 					Flux<?> flux = reader.read(actualType, elementType, request, response, readHints);
 					flux = flux.onErrorResume(ex -> Flux.error(handleReadError(bodyParam, ex)));
-					if (missingBodyError != null) {
-						flux = flux.switchIfEmpty(Flux.error(missingBodyError));
+					if (isBodyRequired) {
+						flux = flux.switchIfEmpty(Flux.error(() -> handleMissingBody(bodyParam)));
 					}
 					Object[] hints = extractValidationHints(bodyParam);
 					if (hints != null) {
@@ -174,8 +172,8 @@ public abstract class AbstractMessageReaderArgumentResolver extends HandlerMetho
 					// Single-value (with or without reactive type wrapper)
 					Mono<?> mono = reader.readMono(actualType, elementType, request, response, readHints);
 					mono = mono.onErrorResume(ex -> Mono.error(handleReadError(bodyParam, ex)));
-					if (missingBodyError != null) {
-						mono = mono.switchIfEmpty(Mono.error(missingBodyError));
+					if (isBodyRequired) {
+						mono = mono.switchIfEmpty(Mono.error(() -> handleMissingBody(bodyParam)));
 					}
 					Object[] hints = extractValidationHints(bodyParam);
 					if (hints != null) {
@@ -195,8 +193,8 @@ public abstract class AbstractMessageReaderArgumentResolver extends HandlerMetho
 				// Body not empty, back to 415..
 				throw new UnsupportedMediaTypeStatusException(mediaType, this.supportedMediaTypes);
 			});
-			if (missingBodyError != null) {
-				body = body.switchIfEmpty(Mono.error(missingBodyError));
+			if (isBodyRequired) {
+				body = body.switchIfEmpty(Mono.error(() -> handleMissingBody(bodyParam)));
 			}
 			return (adapter != null ? Mono.just(adapter.fromPublisher(body)) : Mono.from(body));
 		}