Failure to discover default value for a primitive should not lead to document its default value

configuration-metadata/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/fieldvalues/javac/JavaCompilerFieldValuesParser.java

@@ -209,7 +209,7 @@ private Object getValue(String variableType, ExpressionTree expression, Object d
 				}
 				return null;
 			}
-			return defaultValue;
+			return null;
 		}
 
 		private Object getFactoryValue(ExpressionTree expression, Object factoryValue) {

configuration-metadata/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/metadata/JsonConverter.java

@@ -167,6 +167,9 @@ private void putHintValue(JSONObject jsonObject, Object value) throws Exception
 	}
 
 	private void putDefaultValue(JSONObject jsonObject, Object value) throws Exception {
+		if (value == null) {
+			return;
+		}
 		Object defaultValue = extractItemValue(value);
 		jsonObject.put("defaultValue", defaultValue);
 	}

configuration-metadata/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/ConfigurationMetadataAnnotationProcessorTests.java

@@ -31,6 +31,7 @@
 import org.springframework.boot.configurationprocessor.metadata.Metadata;
 import org.springframework.boot.configurationprocessor.test.CompiledMetadataReader;
 import org.springframework.boot.configurationprocessor.test.TestConfigurationMetadataAnnotationProcessor;
+import org.springframework.boot.configurationsample.arithmetic.ArithmeticExpressionProperties;
 import org.springframework.boot.configurationsample.deprecation.Dbcp2Configuration;
 import org.springframework.boot.configurationsample.method.NestedPropertiesMethod;
 import org.springframework.boot.configurationsample.record.ExampleRecord;
@@ -118,6 +119,7 @@
  * @author Pavel Anisimov
  * @author Scott Frederick
  * @author Moritz Halbritter
+ * @author Hyeon Jae Kim
  */
 class ConfigurationMetadataAnnotationProcessorTests extends AbstractMetadataGenerationTests {
 
@@ -627,6 +629,21 @@ void shouldIgnoreProperties() {
 		assertThat(metadata.getIgnored()).containsExactly(ItemIgnore.forProperty("ignored.prop3"));
 	}
 
+	@Test
+	void arithmeticExpressionPropertiesShouldOmitUnknownDefaultValues(){
+		ConfigurationMetadata metadata = compile(ArithmeticExpressionProperties.class);
+		assertThat(metadata).has(Metadata.withProperty("arithmetic.calculated", Integer.class)
+			.fromSource(ArithmeticExpressionProperties.class));
+		assertThat(metadata).has(Metadata.withProperty("arithmetic.literal", Integer.class)
+			.fromSource(ArithmeticExpressionProperties.class)
+			.withDefaultValue(100));
+		assertThat(metadata).has(Metadata.withProperty("arithmetic.simple-flag", Boolean.class)
+			.fromSource(ArithmeticExpressionProperties.class)
+			.withDefaultValue(true));
+		assertThat(metadata).has(Metadata.withProperty("arithmetic.complex-flag", Boolean.class)
+			.fromSource(ArithmeticExpressionProperties.class));
+	}
+
 	@Nested
 	class SourceTests {
 

configuration-metadata/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/arithmetic/ArithmeticExpressionProperties.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2012-present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.configurationsample.arithmetic;
+
+import org.springframework.boot.configurationsample.ConfigurationProperties;
+
+/**
+ * Configuration properties with arithmetic expressions to test metadata generation for
+ * values that cannot be inferred at compile time. Used to verify that primitive types
+ * with unknown default values omit the defaultValue field in the generated metadata.
+ *
+ * @author Hyeon Jae Kim
+ */
+@ConfigurationProperties(prefix = "arithmetic")
+public class ArithmeticExpressionProperties {
+
+	/**
+	 * A value calculated using arithmetic expression that cannot be inferred.
+	 */
+	private int calculated = 10 * 10;
+
+	/**
+	 * A literal value that can be inferred.
+	 */
+	private int literal = 100;
+
+	/**
+	 * A boolean expression that cannot be inferred.
+	 */
+	private boolean complexFlag = !false;
+
+	/**
+	 * A simple boolean literal.
+	 */
+	private boolean simpleFlag = true;
+
+	public int getCalculated() {
+		return this.calculated;
+	}
+
+	public void setCalculated(int calculated) {
+		this.calculated = calculated;
+	}
+
+	public int getLiteral() {
+		return this.literal;
+	}
+
+	public void setLiteral(int literal) {
+		this.literal = literal;
+	}
+
+	public boolean isComplexFlag() {
+		return this.complexFlag;
+	}
+
+	public void setComplexFlag(boolean complexFlag) {
+		this.complexFlag = complexFlag;
+	}
+
+	public boolean isSimpleFlag() {
+		return this.simpleFlag;
+	}
+
+	public void setSimpleFlag(boolean simpleFlag) {
+		this.simpleFlag = simpleFlag;
+	}
+
+}