Warn about ResponseEntity-ProblemDetail status mismatch

Closes gh-29378

Author: rstoyanchev

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

@@ -159,6 +159,13 @@ else if (returnValue instanceof HttpHeaders) {
 					URI path = URI.create(exchange.getRequest().getPath().value());
 					detail.setInstance(path);
 				}
+				if (logger.isWarnEnabled() && httpEntity instanceof ResponseEntity<?> responseEntity) {
+					if (responseEntity.getStatusCode().value() != detail.getStatus()) {
+						logger.warn(actualParameter.getExecutable().toGenericString() +
+								" returned ResponseEntity: " + responseEntity + ", but its status" +
+								" doesn't match the ProblemDetail status: " + detail.getStatus());
+					}
+				}
 			}
 
 			if (httpEntity instanceof ResponseEntity<?> responseEntity) {

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.java

@@ -197,6 +197,13 @@ else if (returnValue instanceof ProblemDetail detail) {
 				URI path = URI.create(inputMessage.getServletRequest().getRequestURI());
 				detail.setInstance(path);
 			}
+			if (logger.isWarnEnabled() && httpEntity instanceof ResponseEntity<?> responseEntity) {
+				if (responseEntity.getStatusCode().value() != detail.getStatus()) {
+					logger.warn(returnType.getExecutable().toGenericString() +
+							" returned ResponseEntity: " + responseEntity + ", but its status" +
+							" doesn't match the ProblemDetail status: " + detail.getStatus());
+				}
+			}
 		}
 
 		HttpHeaders outputHeaders = outputMessage.getHeaders();