Apply default property inclusion to content

Previously, the setting was only applied to values. This worked
for POJOs but had no effect on maps.

Fixes gh-48343

module/spring-boot-jackson/src/main/java/org/springframework/boot/jackson/autoconfigure/JacksonAutoConfiguration.java

@@ -29,6 +29,7 @@ import java.util.function.BiConsumer;
 import java.util.stream.Stream;
 
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.annotation.PropertyAccessor;
 import org.jspecify.annotations.Nullable;
 import tools.jackson.databind.JacksonModule;
@@ -371,9 +372,10 @@ public final class JacksonAutoConfiguration {
 			if (this.jacksonProperties.isFindAndAddModules()) {
 				builder.findAndAddModules(getClass().getClassLoader());
 			}
-			if (this.jacksonProperties.getDefaultPropertyInclusion() != null) {
-				builder.changeDefaultPropertyInclusion(
-						(handler) -> handler.withValueInclusion(this.jacksonProperties.getDefaultPropertyInclusion()));
+			Include propertyInclusion = this.jacksonProperties.getDefaultPropertyInclusion();
+			if (propertyInclusion != null) {
+				builder.changeDefaultPropertyInclusion((handler) -> handler.withValueInclusion(propertyInclusion)
+					.withContentInclusion(propertyInclusion));
 			}
 			if (this.jacksonProperties.getTimeZone() != null) {
 				builder.defaultTimeZone(this.jacksonProperties.getTimeZone());

module/spring-boot-jackson/src/test/java/org/springframework/boot/jackson/autoconfigure/JacksonAutoConfigurationTests.java

@@ -436,9 +436,11 @@ class JacksonAutoConfigurationTests {
 
 	@EnumSource
 	@ParameterizedTest
-	void defaultSerializationInclusion(MapperType mapperType) {
+	void defaultPropertyInclusion(MapperType mapperType) {
 		this.contextRunner.run((context) -> {
 			ObjectMapper mapper = mapperType.getMapper(context);
+			assertThat(mapper.serializationConfig().getDefaultPropertyInclusion().getContentInclusion())
+				.isEqualTo(JsonInclude.Include.USE_DEFAULTS);
 			assertThat(mapper.serializationConfig().getDefaultPropertyInclusion().getValueInclusion())
 				.isEqualTo(JsonInclude.Include.USE_DEFAULTS);
 		});
@@ -446,9 +448,11 @@ class JacksonAutoConfigurationTests {
 
 	@EnumSource
 	@ParameterizedTest
-	void customSerializationInclusion(MapperType mapperType) {
+	void customPropertyInclusion(MapperType mapperType) {
 		this.contextRunner.withPropertyValues("spring.jackson.default-property-inclusion:non_null").run((context) -> {
 			ObjectMapper mapper = mapperType.getMapper(context);
+			assertThat(mapper.serializationConfig().getDefaultPropertyInclusion().getContentInclusion())
+				.isEqualTo(JsonInclude.Include.NON_NULL);
 			assertThat(mapper.serializationConfig().getDefaultPropertyInclusion().getValueInclusion())
 				.isEqualTo(JsonInclude.Include.NON_NULL);
 		});