Restore HttpMessageConverters ordering

Temporarily add reordering logic to `HttpMessageConverters` to restore
the Spring Boot 3.5 order.

See gh-46221

Author: philwebb

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/HttpMessageConverters.java

@@ -26,8 +26,11 @@
 import java.util.Map;
 
 import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.cbor.MappingJackson2CborHttpMessageConverter;
+import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
 import org.springframework.http.converter.xml.AbstractXmlHttpMessageConverter;
+import org.springframework.http.converter.xml.MappingJackson2XmlHttpMessageConverter;
 import org.springframework.util.ClassUtils;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
@@ -184,13 +187,14 @@ private List<HttpMessageConverter<?>> getDefaultConverters() {
 		List<HttpMessageConverter<?>> converters = new ArrayList<>();
 		if (ClassUtils.isPresent("org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport",
 				null)) {
-			converters.addAll(new WebMvcConfigurationSupport() {
+			List<HttpMessageConverter<?>> webMvcConverters = new WebMvcConfigurationSupport() {
 
 				public List<HttpMessageConverter<?>> defaultMessageConverters() {
 					return super.getMessageConverters();
 				}
 
-			}.defaultMessageConverters());
+			}.defaultMessageConverters();
+			converters.addAll(reorderAllEncompassingFormHttpMessageConverterBeforeJackson(webMvcConverters));
 		}
 		else {
 			converters.addAll(new RestTemplate().getMessageConverters());
@@ -199,6 +203,30 @@ public List<HttpMessageConverter<?>> defaultMessageConverters() {
 		return converters;
 	}
 
+	@SuppressWarnings("removal")
+	private List<HttpMessageConverter<?>> reorderAllEncompassingFormHttpMessageConverterBeforeJackson(
+			List<HttpMessageConverter<?>> converters) {
+		List<HttpMessageConverter<?>> reordered = new ArrayList<>();
+		for (int i = 0; i < converters.size(); i++) {
+			HttpMessageConverter<?> converter = converters.get(i);
+			if (converter == null) {
+				continue;
+			}
+			if (converter instanceof MappingJackson2XmlHttpMessageConverter
+					|| converter instanceof MappingJackson2HttpMessageConverter
+					|| converter instanceof MappingJackson2CborHttpMessageConverter) {
+				for (int j = i; j < converters.size(); j++) {
+					if (converters.get(j) instanceof AllEncompassingFormHttpMessageConverter) {
+						reordered.add(converters.get(j));
+						converters.set(j, null);
+					}
+				}
+			}
+			reordered.add(converter);
+		}
+		return reordered;
+	}
+
 	@SuppressWarnings("removal")
 	private void reorderXmlConvertersToEnd(List<HttpMessageConverter<?>> converters) {
 		List<HttpMessageConverter<?>> xml = new ArrayList<>();

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/http/HttpMessageConvertersTests.java

@@ -56,9 +56,9 @@ void containsDefaults() {
 		}
 		assertThat(converterClasses).containsExactly(ByteArrayHttpMessageConverter.class,
 				StringHttpMessageConverter.class, ResourceHttpMessageConverter.class,
-				ResourceRegionHttpMessageConverter.class, MappingJackson2HttpMessageConverter.class,
-				MappingJackson2CborHttpMessageConverter.class, MappingJackson2YamlHttpMessageConverter.class,
-				AllEncompassingFormHttpMessageConverter.class, MappingJackson2XmlHttpMessageConverter.class);
+				ResourceRegionHttpMessageConverter.class, AllEncompassingFormHttpMessageConverter.class,
+				MappingJackson2HttpMessageConverter.class, MappingJackson2CborHttpMessageConverter.class,
+				MappingJackson2YamlHttpMessageConverter.class, MappingJackson2XmlHttpMessageConverter.class);
 	}
 
 	@Test
@@ -126,9 +126,9 @@ protected List<HttpMessageConverter<?>> postProcessConverters(List<HttpMessageCo
 		}
 		assertThat(converterClasses).containsExactly(ByteArrayHttpMessageConverter.class,
 				StringHttpMessageConverter.class, ResourceHttpMessageConverter.class,
-				ResourceRegionHttpMessageConverter.class, MappingJackson2HttpMessageConverter.class,
-				MappingJackson2CborHttpMessageConverter.class, MappingJackson2YamlHttpMessageConverter.class,
-				AllEncompassingFormHttpMessageConverter.class);
+				ResourceRegionHttpMessageConverter.class, AllEncompassingFormHttpMessageConverter.class,
+				MappingJackson2HttpMessageConverter.class, MappingJackson2CborHttpMessageConverter.class,
+				MappingJackson2YamlHttpMessageConverter.class);
 	}
 
 	@Test