Revise DynamicPropertyRegistrar support

With this commit, a DynamicValuesPropertySource is now created and
registered with the Environment on demand whenever a
DefaultDynamicPropertyRegistry is created, which only occurs once in
DynamicPropertiesContextCustomizer and once in
DynamicPropertyRegistrarBeanInitializer.

In addition, DefaultDynamicPropertyRegistry now operates on the
valueSuppliers map stored in the singleton DynamicValuesPropertySource
registered with the Environment, which allows @⁠DynamicPropertySource
methods and DynamicPropertyRegistrar beans to transparently populate
the same DynamicValuesPropertySource.

See spring-projectsgh-33501

spring-test/src/main/java/org/springframework/test/context/support/DefaultDynamicPropertyRegistry.java

@@ -16,16 +16,10 @@
 
 package org.springframework.test.context.support;
 
-import java.util.Collections;
-import java.util.LinkedHashMap;
 import java.util.Map;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Supplier;
 
 import org.springframework.core.env.ConfigurableEnvironment;
-import org.springframework.core.env.MutablePropertySources;
-import org.springframework.core.env.PropertySource;
 import org.springframework.test.context.DynamicPropertyRegistry;
 import org.springframework.util.Assert;
 
@@ -37,43 +31,21 @@
  */
 final class DefaultDynamicPropertyRegistry implements DynamicPropertyRegistry {
 
-	final Map<String, Supplier<Object>> valueSuppliers = Collections.synchronizedMap(new LinkedHashMap<>());
+	private final Map<String, Supplier<Object>> valueSuppliers;
 
-	private final ConfigurableEnvironment environment;
 
-	private final boolean lazilyRegisterPropertySource;
-
-	private final Lock propertySourcesLock = new ReentrantLock();
-
-
-	DefaultDynamicPropertyRegistry(ConfigurableEnvironment environment, boolean lazilyRegisterPropertySource) {
-		this.environment = environment;
-		this.lazilyRegisterPropertySource = lazilyRegisterPropertySource;
+	DefaultDynamicPropertyRegistry(ConfigurableEnvironment environment) {
+		DynamicValuesPropertySource dynamicValuesPropertySource =
+				DynamicValuesPropertySource.getOrCreate(environment);
+		this.valueSuppliers = dynamicValuesPropertySource.valueSuppliers;
 	}
 
 
 	@Override
 	public void add(String name, Supplier<Object> valueSupplier) {
 		Assert.hasText(name, "'name' must not be null or blank");
 		Assert.notNull(valueSupplier, "'valueSupplier' must not be null");
-		if (this.lazilyRegisterPropertySource) {
-			ensurePropertySourceIsRegistered();
-		}
 		this.valueSuppliers.put(name, valueSupplier);
 	}
 
-	private void ensurePropertySourceIsRegistered() {
-		MutablePropertySources propertySources = this.environment.getPropertySources();
-		this.propertySourcesLock.lock();
-		try {
-			PropertySource<?> ps = propertySources.get(DynamicValuesPropertySource.PROPERTY_SOURCE_NAME);
-			if (ps == null) {
-				propertySources.addFirst(new DynamicValuesPropertySource(this.valueSuppliers));
-			}
-		}
-		finally {
-			this.propertySourcesLock.unlock();
-		}
-	}
-
 }

spring-test/src/main/java/org/springframework/test/context/support/DynamicPropertiesContextCustomizer.java

@@ -26,20 +26,20 @@
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.env.ConfigurableEnvironment;
-import org.springframework.core.env.MutablePropertySources;
 import org.springframework.lang.Nullable;
 import org.springframework.test.context.ContextCustomizer;
 import org.springframework.test.context.DynamicPropertyRegistry;
-import org.springframework.test.context.DynamicPropertySource;
 import org.springframework.test.context.MergedContextConfiguration;
 import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
 
 /**
  * {@link ContextCustomizer} which supports
- * {@link DynamicPropertySource @DynamicPropertySource} methods and registers a
- * {@link DynamicPropertyRegistry} as a singleton bean in the container for use
- * in {@code @Configuration} classes and {@code @Bean} methods.
+ * {@link org.springframework.test.context.DynamicPropertySource @DynamicPropertySource}
+ * methods and registers a {@link DynamicPropertyRegistrarBeanInitializer} in the
+ * container to eagerly initialize
+ * {@link org.springframework.test.context.DynamicPropertyRegistrar DynamicPropertyRegistrar}
+ * beans.
  *
  * @author Phillip Webb
  * @author Sam Brannen
@@ -79,10 +79,7 @@ public void customizeContext(ConfigurableApplicationContext context, MergedConte
 
 		if (!this.methods.isEmpty()) {
 			ConfigurableEnvironment environment = context.getEnvironment();
-			DefaultDynamicPropertyRegistry dynamicPropertyRegistry =
-					new DefaultDynamicPropertyRegistry(environment, false);
-			MutablePropertySources propertySources = environment.getPropertySources();
-			propertySources.addFirst(new DynamicValuesPropertySource(dynamicPropertyRegistry.valueSuppliers));
+			DefaultDynamicPropertyRegistry dynamicPropertyRegistry = new DefaultDynamicPropertyRegistry(environment);
 			this.methods.forEach(method -> {
 				ReflectionUtils.makeAccessible(method);
 				ReflectionUtils.invokeMethod(method, null, dynamicPropertyRegistry);

spring-test/src/main/java/org/springframework/test/context/support/DynamicPropertyRegistrarBeanInitializer.java

@@ -60,9 +60,7 @@ public void initialize(ListableBeanFactory beanFactory) {
 		String[] beanNames = BeanFactoryUtils.beanNamesForTypeIncludingAncestors(
 				beanFactory, DynamicPropertyRegistrar.class);
 		if (beanNames.length > 0) {
-			DefaultDynamicPropertyRegistry dynamicPropertyRegistry =
-					new DefaultDynamicPropertyRegistry(this.environment, true);
-
+			DefaultDynamicPropertyRegistry dynamicPropertyRegistry = new DefaultDynamicPropertyRegistry(this.environment);
 			for (String name : beanNames) {
 				if (logger.isDebugEnabled()) {
 					logger.debug("Eagerly initializing DynamicPropertyRegistrar bean '%s'".formatted(name));

spring-test/src/main/java/org/springframework/test/context/support/DynamicValuesPropertySource.java

@@ -17,10 +17,16 @@
 package org.springframework.test.context.support;
 
 import java.util.Collections;
+import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Supplier;
 
+import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.MapPropertySource;
+import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.PropertySource;
 import org.springframework.lang.Nullable;
 import org.springframework.util.function.SupplierUtils;
 
@@ -36,9 +42,18 @@ class DynamicValuesPropertySource extends MapPropertySource {
 
 	static final String PROPERTY_SOURCE_NAME = "Dynamic Test Properties";
 
+	private static final Lock propertySourcesLock = new ReentrantLock();
+
+	final Map<String, Supplier<Object>> valueSuppliers;
+
+
+	DynamicValuesPropertySource() {
+		this(Collections.synchronizedMap(new LinkedHashMap<>()));
+	}
 
 	DynamicValuesPropertySource(Map<String, Supplier<Object>> valueSuppliers) {
 		super(PROPERTY_SOURCE_NAME, Collections.unmodifiableMap(valueSuppliers));
+		this.valueSuppliers = valueSuppliers;
 	}
 
 
@@ -48,4 +63,29 @@ public Object getProperty(String name) {
 		return SupplierUtils.resolve(super.getProperty(name));
 	}
 
+
+	static DynamicValuesPropertySource getOrCreate(ConfigurableEnvironment environment) {
+		propertySourcesLock.lock();
+		try {
+			MutablePropertySources propertySources = environment.getPropertySources();
+			PropertySource<?> ps = propertySources.get(PROPERTY_SOURCE_NAME);
+			if (ps instanceof DynamicValuesPropertySource dynamicValuesPropertySource) {
+				return dynamicValuesPropertySource;
+			}
+			else if (ps == null) {
+				DynamicValuesPropertySource dynamicValuesPropertySource = new DynamicValuesPropertySource();
+				propertySources.addFirst(dynamicValuesPropertySource);
+				return dynamicValuesPropertySource;
+			}
+			else {
+				throw new IllegalStateException(
+						"PropertySource with name '%s' must be a DynamicValuesPropertySource"
+							.formatted(PROPERTY_SOURCE_NAME));
+			}
+		}
+		finally {
+			propertySourcesLock.unlock();
+		}
+	}
+
 }

spring-test/src/test/java/org/springframework/test/context/DynamicPropertyRegistrarIntegrationTests.java

@@ -39,10 +39,12 @@
  * @see DynamicPropertySourceIntegrationTests
  */
 @SpringJUnitConfig
-@TestPropertySource(properties = "api.url: https://example.com/test")
+@TestPropertySource(properties = "api.url.1: https://example.com/test")
 class DynamicPropertyRegistrarIntegrationTests {
 
-	private static final String API_URL = "api.url";
+	private static final String API_URL_1 = "api.url.1";
+	private static final String API_URL_2 = "api.url.2";
+
 
 	@Test
 	void customDynamicPropertyRegistryCanExistInApplicationContext(
@@ -55,43 +57,49 @@ void customDynamicPropertyRegistryCanExistInApplicationContext(
 
 	@Test
 	void dynamicPropertySourceOverridesTestPropertySource(@Autowired ConfigurableEnvironment env) {
-		assertApiUrlIsDynamic(env.getProperty(API_URL));
+		assertApiUrlIsDynamic1(env.getProperty(API_URL_1));
 
 		MutablePropertySources propertySources = env.getPropertySources();
 		assertThat(propertySources.size()).isGreaterThanOrEqualTo(4);
 		assertThat(propertySources.contains("Inlined Test Properties")).isTrue();
 		assertThat(propertySources.contains("Dynamic Test Properties")).isTrue();
-		assertThat(propertySources.get("Inlined Test Properties").getProperty(API_URL)).isEqualTo("https://example.com/test");
-		assertThat(propertySources.get("Dynamic Test Properties").getProperty(API_URL)).isEqualTo("https://example.com/dynamic");
+		assertThat(propertySources.get("Inlined Test Properties").getProperty(API_URL_1)).isEqualTo("https://example.com/test");
+		assertThat(propertySources.get("Dynamic Test Properties").getProperty(API_URL_1)).isEqualTo("https://example.com/dynamic/1");
+		assertThat(propertySources.get("Dynamic Test Properties").getProperty(API_URL_2)).isEqualTo("https://example.com/dynamic/2");
 	}
 
 	@Test
-	void testReceivesDynamicProperty(@Value("${api.url}") String apiUrl) {
-		assertApiUrlIsDynamic(apiUrl);
+	void testReceivesDynamicProperties(@Value("${api.url.1}") String apiUrl1, @Value("${api.url.2}") String apiUrl2) {
+		assertApiUrlIsDynamic1(apiUrl1);
+		assertApiUrlIsDynamic2(apiUrl2);
 	}
 
 	@Test
 	void environmentInjectedServiceCanRetrieveDynamicProperty(@Autowired EnvironmentInjectedService service) {
-		assertApiUrlIsDynamic(service);
+		assertApiUrlIsDynamic1(service);
 	}
 
 	@Test
 	void constructorInjectedServiceReceivesDynamicProperty(@Autowired ConstructorInjectedService service) {
-		assertApiUrlIsDynamic(service);
+		assertApiUrlIsDynamic1(service);
 	}
 
 	@Test
 	void setterInjectedServiceReceivesDynamicProperty(@Autowired SetterInjectedService service) {
-		assertApiUrlIsDynamic(service);
+		assertApiUrlIsDynamic1(service);
 	}
 
 
-	private static void assertApiUrlIsDynamic(ApiUrlClient service) {
-		assertApiUrlIsDynamic(service.getApiUrl());
+	private static void assertApiUrlIsDynamic1(ApiUrlClient service) {
+		assertApiUrlIsDynamic1(service.getApiUrl());
+	}
+
+	private static void assertApiUrlIsDynamic1(String apiUrl) {
+		assertThat(apiUrl).isEqualTo("https://example.com/dynamic/1");
 	}
 
-	private static void assertApiUrlIsDynamic(String apiUrl) {
-		assertThat(apiUrl).isEqualTo("https://example.com/dynamic");
+	private static void assertApiUrlIsDynamic2(String apiUrl) {
+		assertThat(apiUrl).isEqualTo("https://example.com/dynamic/2");
 	}
 
 
@@ -109,8 +117,13 @@ ApiServer apiServer() {
 		// context which further ensures that the dynamic "api.url" property is
 		// available to all standard singleton beans.
 		@Bean
-		DynamicPropertyRegistrar apiServerProperties(ApiServer apiServer) {
-			return registry -> registry.add(API_URL, apiServer::getUrl);
+		DynamicPropertyRegistrar apiServerProperties1(ApiServer apiServer) {
+			return registry -> registry.add(API_URL_1, () -> apiServer.getUrl() + "/1");
+		}
+
+		@Bean
+		DynamicPropertyRegistrar apiServerProperties2(ApiServer apiServer) {
+			return registry -> registry.add(API_URL_2, () -> apiServer.getUrl() + "/2");
 		}
 
 		@Bean
@@ -138,7 +151,7 @@ static class EnvironmentInjectedService implements ApiUrlClient {
 
 		@Override
 		public String getApiUrl() {
-			return this.env.getProperty(API_URL);
+			return this.env.getProperty(API_URL_1);
 		}
 	}
 
@@ -147,7 +160,7 @@ static class ConstructorInjectedService implements ApiUrlClient {
 		private final String apiUrl;
 
 
-		ConstructorInjectedService(@Value("${api.url}") String apiUrl) {
+		ConstructorInjectedService(@Value("${api.url.1}") String apiUrl) {
 			this.apiUrl = apiUrl;
 		}
 
@@ -163,7 +176,7 @@ static class SetterInjectedService implements ApiUrlClient {
 
 
 		@Autowired
-		void setApiUrl(@Value("${api.url}") String apiUrl) {
+		void setApiUrl(@Value("${api.url.1}") String apiUrl) {
 			this.apiUrl = apiUrl;
 		}
 

spring-test/src/test/java/org/springframework/test/context/DynamicPropertySourceIntegrationTests.java

@@ -49,6 +49,7 @@
 class DynamicPropertySourceIntegrationTests {
 
 	private static final String TEST_CONTAINER_IP = "test.container.ip";
+	private static final String MAGIC_WORD = "magic.word";
 
 	static {
 		System.setProperty(TEST_CONTAINER_IP, "system");
@@ -91,11 +92,11 @@ void dynamicPropertySourceOverridesTestPropertySourceAndSystemProperty(@Autowire
 		assertThat(propertySources.contains("Inlined Test Properties")).isTrue();
 		assertThat(propertySources.contains("systemProperties")).isTrue();
 		assertThat(propertySources.get("Dynamic Test Properties").getProperty(TEST_CONTAINER_IP)).isEqualTo("127.0.0.1");
-		// assertThat(propertySources.get("Dynamic Test Properties").getProperty("magic.word")).isEqualTo("enigma");
+		assertThat(propertySources.get("Dynamic Test Properties").getProperty(MAGIC_WORD)).isEqualTo("enigma");
 		assertThat(propertySources.get("Inlined Test Properties").getProperty(TEST_CONTAINER_IP)).isEqualTo("test");
 		assertThat(propertySources.get("systemProperties").getProperty(TEST_CONTAINER_IP)).isEqualTo("system");
 		assertThat(env.getProperty(TEST_CONTAINER_IP)).isEqualTo("127.0.0.1");
-		// assertThat(env.getProperty("magic.word")).isEqualTo("enigma");
+		assertThat(env.getProperty(MAGIC_WORD)).isEqualTo("enigma");
 	}
 
 	@Test
@@ -112,7 +113,7 @@ static class Config {
 
 		@Bean
 		DynamicPropertyRegistrar magicWordProperties() {
-			return registry -> registry.add("magic.word", () -> "engima");
+			return registry -> registry.add(MAGIC_WORD, () -> "enigma");
 		}
 
 		@Bean