Support wrapped random property sources

Update `SpringConfigurationPropertySource` so that wrapped random
property sources can be used. It's assumed that wrapped random
sources will use the name of the source as the prefix.

Closes gh-21595

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/SpringConfigurationPropertySource.java

@@ -20,6 +20,7 @@ import java.util.Map;
 import java.util.Random;
 import java.util.function.Function;
 
+import org.springframework.boot.context.properties.source.ConfigurationPropertyName.Form;
 import org.springframework.boot.origin.Origin;
 import org.springframework.boot.origin.PropertySourceOrigin;
 import org.springframework.core.env.EnumerablePropertySource;
@@ -53,8 +54,6 @@ import org.springframework.util.ObjectUtils;
  */
 class SpringConfigurationPropertySource implements ConfigurationPropertySource {
 
-	private static final ConfigurationPropertyName RANDOM = ConfigurationPropertyName.of("random");
-
 	private final PropertySource<?> propertySource;
 
 	private final PropertyMapper mapper;
@@ -184,13 +183,19 @@ class SpringConfigurationPropertySource implements ConfigurationPropertySource {
 	private static Function<ConfigurationPropertyName, ConfigurationPropertyState> getContainsDescendantOfForSource(
 			PropertySource<?> source) {
 		if (source.getSource() instanceof Random) {
-			return SpringConfigurationPropertySource::containsDescendantOfForRandom;
+			return (name) -> containsDescendantOfForRandom("random", name);
+		}
+		if (source.getSource() instanceof PropertySource<?>
+				&& ((PropertySource<?>) source.getSource()).getSource() instanceof Random) {
+			// Assume wrapped random sources use the source name as the prefix
+			return (name) -> containsDescendantOfForRandom(source.getName(), name);
 		}
 		return null;
 	}
 
-	private static ConfigurationPropertyState containsDescendantOfForRandom(ConfigurationPropertyName name) {
-		if (RANDOM.isAncestorOf(name) || name.equals(RANDOM)) {
+	private static ConfigurationPropertyState containsDescendantOfForRandom(String prefix,
+			ConfigurationPropertyName name) {
+		if (name.getNumberOfElements() > 1 && name.getElement(0, Form.DASHED).equals(prefix)) {
 			return ConfigurationPropertyState.PRESENT;
 		}
 		return ConfigurationPropertyState.ABSENT;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/env/RandomValuePropertySource.java

@@ -62,14 +62,14 @@ public class RandomValuePropertySource extends PropertySource<Random> {
 
 	private static final Log logger = LogFactory.getLog(RandomValuePropertySource.class);
 
-	public RandomValuePropertySource(String name) {
-		super(name, new Random());
-	}
-
 	public RandomValuePropertySource() {
 		this(RANDOM_PROPERTY_SOURCE_NAME);
 	}
 
+	public RandomValuePropertySource(String name) {
+		super(name, new Random());
+	}
+
 	@Override
 	public Object getProperty(String name) {
 		if (!name.startsWith(PREFIX)) {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/source/SpringConfigurationPropertySourceTests.java

@@ -153,24 +153,105 @@ class SpringConfigurationPropertySourceTests {
 	void containsDescendantOfWhenRandomSourceAndRandomPropertyReturnsPresent() {
 		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
 				.from(new RandomValuePropertySource());
-		assertThat(source.containsDescendantOf(ConfigurationPropertyName.of("random")))
-				.isEqualTo(ConfigurationPropertyState.PRESENT);
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("random");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.ABSENT);
+		assertThat(source.getConfigurationProperty(name)).isNull();
 	}
 
 	@Test
 	void containsDescendantOfWhenRandomSourceAndRandomPrefixedPropertyReturnsPresent() {
 		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
 				.from(new RandomValuePropertySource());
-		assertThat(source.containsDescendantOf(ConfigurationPropertyName.of("random.something")))
-				.isEqualTo(ConfigurationPropertyState.PRESENT);
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("random.int");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.PRESENT);
+		assertThat(source.getConfigurationProperty(name)).isNotNull();
+	}
+
+	@Test
+	void containsDescendantOfWhenRandomSourceWithDifferentNameAndRandomPrefixedPropertyReturnsPresent() {
+		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
+				.from(new RandomValuePropertySource("different"));
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("random.int");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.PRESENT);
+		assertThat(source.getConfigurationProperty(name)).isNotNull();
 	}
 
 	@Test
 	void containsDescendantOfWhenRandomSourceAndNonRandomPropertyReturnsAbsent() {
 		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
 				.from(new RandomValuePropertySource());
-		assertThat(source.containsDescendantOf(ConfigurationPropertyName.of("abandon.something")))
-				.isEqualTo(ConfigurationPropertyState.ABSENT);
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("abandon.int");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.ABSENT);
+		assertThat(source.getConfigurationProperty(name)).isNull();
+	}
+
+	@Test
+	void containsDescendantOfWhenWrappedRandomSourceAndRandomPropertyReturnsPresent() {
+		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
+				.from(new RandomWrapperPropertySource());
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("cachedrandom");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.ABSENT);
+		assertThat(source.getConfigurationProperty(name)).isNull();
+	}
+
+	@Test
+	void containsDescendantOfWhenWrappedRandomSourceAndRandomPrefixedPropertyReturnsPresent() {
+		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
+				.from(new RandomWrapperPropertySource());
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("cachedrandom.something.int");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.ABSENT);
+		assertThat(source.getConfigurationProperty(name)).isNull();
+	}
+
+	@Test
+	void containsDescendantOfWhenWrappedRandomSourceWithMatchingNameAndRandomPrefixedPropertyReturnsPresent() {
+		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
+				.from(new RandomWrapperPropertySource("cachedrandom"));
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("cachedrandom.something.int");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.PRESENT);
+		assertThat(source.getConfigurationProperty(name)).isNotNull();
+	}
+
+	@Test
+	void containsDescendantOfWhenWrappedRandomSourceAndRandomDashPrefixedPropertyReturnsPresent() {
+		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
+				.from(new RandomWrapperPropertySource());
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("cached-random.something.int");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.ABSENT);
+		assertThat(source.getConfigurationProperty(name)).isNull();
+	}
+
+	@Test
+	void containsDescendantOfWhenWrappedRandomSourceAndNonRandomPropertyReturnsAbsent() {
+		SpringConfigurationPropertySource source = SpringConfigurationPropertySource
+				.from(new RandomWrapperPropertySource());
+		ConfigurationPropertyName name = ConfigurationPropertyName.of("abandon.something.int");
+		assertThat(source.containsDescendantOf(name)).isEqualTo(ConfigurationPropertyState.ABSENT);
+		assertThat(source.getConfigurationProperty(name)).isNull();
+	}
+
+	static class RandomWrapperPropertySource extends PropertySource<RandomValuePropertySource> {
+
+		private final String prefix;
+
+		RandomWrapperPropertySource() {
+			this("cachedRandom");
+		}
+
+		RandomWrapperPropertySource(String name) {
+			super(name, new RandomValuePropertySource());
+			this.prefix = name + ".";
+		}
+
+		@Override
+		public Object getProperty(String name) {
+			name = name.toLowerCase();
+			if (!name.startsWith(this.prefix)) {
+				return null;
+			}
+			return getSource().getProperty("random." + name.substring(this.prefix.length()));
+		}
+
 	}
 
 	/**