Call getErrorAttributes() only once

Refine the fix introduced in commit 60b7e6c so that the
`getErrorAttributes()` method is not called multiple times. If the
status is missing, the `DefaultErrorWebExceptionHandler` will now
call an internal `DefaultErrorAttributes` instance in order to obtain
the actual status result.

Fixes gh-41732

Author: philwebb

Diff for: spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/error/DefaultErrorWebExceptionHandler.java

@@ -30,6 +30,7 @@
 import org.springframework.boot.autoconfigure.web.WebProperties.Resources;
 import org.springframework.boot.web.error.ErrorAttributeOptions;
 import org.springframework.boot.web.error.ErrorAttributeOptions.Include;
+import org.springframework.boot.web.reactive.error.DefaultErrorAttributes;
 import org.springframework.boot.web.reactive.error.ErrorAttributes;
 import org.springframework.context.ApplicationContext;
 import org.springframework.http.HttpStatus;
@@ -94,6 +95,8 @@ public class DefaultErrorWebExceptionHandler extends AbstractErrorWebExceptionHa
 
 	private static final ErrorAttributeOptions ONLY_STATUS = ErrorAttributeOptions.of(Include.STATUS);
 
+	private static final DefaultErrorAttributes defaultErrorAttributes = new DefaultErrorAttributes();
+
 	private final ErrorProperties errorProperties;
 
 	/**
@@ -121,8 +124,8 @@ protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes erro
 	 * @return a {@code Publisher} of the HTTP response
 	 */
 	protected Mono<ServerResponse> renderErrorView(ServerRequest request) {
-		int status = getHttpStatus(getErrorAttributes(request, ONLY_STATUS));
 		Map<String, Object> errorAttributes = getErrorAttributes(request, MediaType.TEXT_HTML);
+		int status = getHttpStatus(request, errorAttributes);
 		ServerResponse.BodyBuilder responseBody = ServerResponse.status(status).contentType(TEXT_HTML_UTF8);
 		return Flux.just(getData(status).toArray(new String[] {}))
 			.flatMap((viewName) -> renderErrorView(viewName, responseBody, errorAttributes))
@@ -148,8 +151,8 @@ private List<String> getData(int errorStatus) {
 	 * @return a {@code Publisher} of the HTTP response
 	 */
 	protected Mono<ServerResponse> renderErrorResponse(ServerRequest request) {
-		int status = getHttpStatus(getErrorAttributes(request, ONLY_STATUS));
 		Map<String, Object> errorAttributes = getErrorAttributes(request, MediaType.ALL);
+		int status = getHttpStatus(request, errorAttributes);
 		return ServerResponse.status(status)
 			.contentType(MediaType.APPLICATION_JSON)
 			.body(BodyInserters.fromValue(errorAttributes));
@@ -234,6 +237,11 @@ protected boolean isIncludePath(ServerRequest request, MediaType produces) {
 		};
 	}
 
+	private int getHttpStatus(ServerRequest request, Map<String, Object> errorAttributes) {
+		return getHttpStatus(errorAttributes.containsKey("status") ? errorAttributes
+				: defaultErrorAttributes.getErrorAttributes(request, ONLY_STATUS));
+	}
+
 	/**
 	 * Get the HTTP error status information from the error map.
 	 * @param errorAttributes the current error information

Diff for: spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/reactive/error/DefaultErrorWebExceptionHandlerIntegrationTests.java

@@ -18,6 +18,7 @@
 
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.Map;
 
 import jakarta.validation.Valid;
@@ -597,6 +598,21 @@ void customErrorWebExceptionHandlerWithoutStatus() {
 		});
 	}
 
+	@Test
+	void customErrorAttributesWithoutStatus() {
+		this.contextRunner.withUserConfiguration(CustomErrorAttributesWithoutStatus.class).run((context) -> {
+			WebTestClient client = getWebClient(context);
+			client.get()
+				.uri("/badRequest")
+				.exchange()
+				.expectStatus()
+				.isBadRequest()
+				.expectBody()
+				.jsonPath("status")
+				.doesNotExist();
+		});
+	}
+
 	private String getErrorTemplatesLocation() {
 		String packageName = getClass().getPackage().getName();
 		return "classpath:/" + packageName.replace('.', '/') + "/templates/";
@@ -686,6 +702,7 @@ static class CustomErrorAttributesWithoutDelegation {
 		@Bean
 		ErrorAttributes errorAttributes() {
 			return new DefaultErrorAttributes() {
+
 				@Override
 				public Map<String, Object> getErrorAttributes(ServerRequest request, ErrorAttributeOptions options) {
 					Map<String, Object> errorAttributes = new HashMap<>();
@@ -724,4 +741,23 @@ protected ErrorAttributeOptions getErrorAttributeOptions(ServerRequest request,
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class CustomErrorAttributesWithoutStatus {
+
+		@Bean
+		ErrorAttributes errorAttributes() {
+			return new DefaultErrorAttributes() {
+
+				@Override
+				public Map<String, Object> getErrorAttributes(ServerRequest request, ErrorAttributeOptions options) {
+					Map<String, Object> attributes = new LinkedHashMap<>(super.getErrorAttributes(request, options));
+					attributes.remove("status");
+					return attributes;
+				}
+
+			};
+		}
+
+	}
+
 }