Merge pull request #29010 from An1s9n

* gh-29010:
  Polish "Allow @DefaultValue to be used on record components"
  Allow @DefaultValue to be used on record components

Closes gh-29010

Author: wilkinsona

spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/external-config.adoc

@@ -719,7 +719,8 @@ Unless your record has multiple constructors, there is no need to use `@Construc
 
 Nested members of a constructor bound class (such as `Security` in the example above) will also be bound through their constructor.
 
-Default values can be specified using `@DefaultValue` and the same conversion service will be applied to coerce the `String` value to the target type of a missing property.
+Default values can be specified using `@DefaultValue` on constructor parameters and record components.
+The conversion service will be applied to coerce the annotation's `String` value to the target type of a missing property.
 By default, if no properties are bound to `Security`, the `MyProperties` instance will contain a `null` value for `security`.
 If you wish you return a non-null instance of `Security` even when no properties are bound to it, you can use an empty `@DefaultValue` annotation to do so:
 

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

@@ -74,6 +74,7 @@
  * @author Andy Wilkinson
  * @author Kris De Volder
  * @author Jonas Keßler
+ * @author Pavel Anisimov
  */
 class ConfigurationMetadataAnnotationProcessorTests extends AbstractMetadataGenerationTests {
 
@@ -445,4 +446,23 @@ void multiConstructorRecordProperties(@TempDir File temp) throws IOException {
 		assertThat(metadata).doesNotHave(Metadata.withProperty("multi.some-integer"));
 	}
 
+	@Test
+	void recordPropertiesWithDefaultValues(@TempDir File temp) throws IOException {
+		File exampleRecord = new File(temp, "ExampleRecord.java");
+		try (PrintWriter writer = new PrintWriter(new FileWriter(exampleRecord))) {
+			writer.println(
+					"@org.springframework.boot.configurationsample.ConfigurationProperties(\"record.defaults\")");
+			writer.println("public record ExampleRecord(");
+			writer.println("@org.springframework.boot.configurationsample.DefaultValue(\"An1s9n\") String someString,");
+			writer.println("@org.springframework.boot.configurationsample.DefaultValue(\"594\") Integer someInteger");
+			writer.println(") {");
+			writer.println("}");
+		}
+		ConfigurationMetadata metadata = compile(exampleRecord);
+		assertThat(metadata)
+				.has(Metadata.withProperty("record.defaults.some-string", String.class).withDefaultValue("An1s9n"));
+		assertThat(metadata)
+				.has(Metadata.withProperty("record.defaults.some-integer", Integer.class).withDefaultValue(594));
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/DefaultValue.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -27,8 +27,9 @@
  * dependency on the real annotation).
  *
  * @author Stephane Nicoll
+ * @author Pavel Anisimov
  */
-@Target({ ElementType.PARAMETER })
+@Target({ ElementType.PARAMETER, ElementType.RECORD_COMPONENT })
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 public @interface DefaultValue {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/DefaultValue.java

@@ -37,10 +37,11 @@
  * must be constant.
  *
  * @author Madhura Bhave
+ * @author Pavel Anisimov
  * @since 2.2.0
  */
 @Retention(RetentionPolicy.RUNTIME)
-@Target({ ElementType.PARAMETER })
+@Target({ ElementType.PARAMETER, ElementType.RECORD_COMPONENT })
 @Documented
 public @interface DefaultValue {
 

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/ValueObjectBinderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -16,23 +16,33 @@
 
 package org.springframework.boot.context.properties.bind;
 
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
 import java.lang.reflect.Constructor;
+import java.net.URL;
+import java.net.URLClassLoader;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.time.LocalDate;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
 
 import org.springframework.boot.context.properties.source.ConfigurationPropertyName;
 import org.springframework.boot.context.properties.source.ConfigurationPropertySource;
 import org.springframework.boot.context.properties.source.MockConfigurationPropertySource;
+import org.springframework.boot.testsupport.compiler.TestCompiler;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.format.annotation.DateTimeFormat;
+import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.util.Assert;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -43,6 +53,7 @@
  *
  * @author Madhura Bhave
  * @author Phillip Webb
+ * @author Pavel Anisimov
  */
 class ValueObjectBinderTests {
 
@@ -357,6 +368,29 @@ void bindToAnnotationNamedParameter() {
 		assertThat(bound.getImportName()).isEqualTo("test");
 	}
 
+	@Test
+	void bindToRecordWithDefaultValue(@TempDir File tempDir) throws IOException, ClassNotFoundException {
+		MockConfigurationPropertySource source = new MockConfigurationPropertySource();
+		source.put("test.record.property1", "value-from-config-1");
+		this.sources.add(source);
+		File recordProperties = new File(tempDir, "RecordProperties.java");
+		try (PrintWriter writer = new PrintWriter(new FileWriter(recordProperties))) {
+			writer.println("public record RecordProperties(");
+			writer.println(
+					"@org.springframework.boot.context.properties.bind.DefaultValue(\"default-value-1\") String property1,");
+			writer.println(
+					"@org.springframework.boot.context.properties.bind.DefaultValue(\"default-value-2\") String property2");
+			writer.println(") {");
+			writer.println("}");
+		}
+		TestCompiler compiler = new TestCompiler(tempDir);
+		compiler.getTask(Arrays.asList(recordProperties)).call();
+		ClassLoader ucl = new URLClassLoader(new URL[] { tempDir.toURI().toURL() });
+		Object bean = this.binder.bind("test.record", Class.forName("RecordProperties", true, ucl)).get();
+		assertThat(ReflectionTestUtils.getField(bean, "property1")).isEqualTo("value-from-config-1");
+		assertThat(ReflectionTestUtils.getField(bean, "property2")).isEqualTo("default-value-2");
+	}
+
 	private void noConfigurationProperty(BindException ex) {
 		assertThat(ex.getProperty()).isNull();
 	}