Ensures HikariDataSource is never re-bound.

Removes HikariDataSource from extra-refreshable and adds it to a new property never-refreshable.

ConfigurationPropertiesRebinder now checks that property and does not rebind beans whose class is in never-refreshable.

fixes gh-687

docs/src/main/asciidoc/spring-cloud-commons.adoc

@@ -184,9 +184,9 @@ Then, the next time something borrows a connection from the pool, it gets one wi
 Sometimes, it might even be mandatory to apply the `@RefreshScope` annotation on some beans that can be only initialized once.
 If a bean is "`immutable`", you have to either annotate the bean with `@RefreshScope` or specify the classname under the property key: `spring.cloud.refresh.extra-refreshable`.
 
-IMPORTANT: If you create a `DataSource` bean yourself and the implementation is a `HikariDataSource`, return the
-most specific type, in this case `HikariDataSource`. Otherwise, you need to set
-`spring.cloud.refresh.extra-refreshable=javax.sql.DataSource`.
+WARNING: If you hava a `DataSource` bean that is a `HikariDataSource`, it can not be
+refreshed. It is the default value for `spring.cloud.refresh.never-refreshable`. Choose a
+different `DataSource` implementation if you need it to be refreshed.
 
 Refresh scope beans are lazy proxies that initialize when they are used (that is, when a method is called), and the scope acts as a cache of initialized values.
 To force a bean to re-initialize on the next method call, you must invalidate its cache entry.

spring-cloud-context/src/main/java/org/springframework/cloud/autoconfigure/RefreshAutoConfiguration.java

@@ -16,7 +16,6 @@
 
 package org.springframework.cloud.autoconfigure;
 
-import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -140,8 +139,7 @@ public class RefreshAutoConfiguration {
 		 * Class names for beans to post process into refresh scope. Useful when you don't
 		 * control the bean definition (e.g. it came from auto-configuration).
 		 */
-		private Set<String> refreshables = new HashSet<>(
-				Arrays.asList("com.zaxxer.hikari.HikariDataSource"));
+		private Set<String> refreshables = new HashSet<>();
 
 		public Set<String> getRefreshable() {
 			return this.refreshables;

spring-cloud-context/src/main/java/org/springframework/cloud/context/properties/ConfigurationPropertiesRebinder.java

@@ -35,6 +35,7 @@ import org.springframework.jmx.export.annotation.ManagedAttribute;
 import org.springframework.jmx.export.annotation.ManagedOperation;
 import org.springframework.jmx.export.annotation.ManagedResource;
 import org.springframework.stereotype.Component;
+import org.springframework.util.StringUtils;
 
 /**
  * Listens for {@link EnvironmentChangeEvent} and rebinds beans that were bound to the
@@ -96,6 +97,11 @@ public class ConfigurationPropertiesRebinder
 					bean = ProxyUtils.getTargetObject(bean);
 				}
 				if (bean != null) {
+					// TODO: determine a more general approach to fix this.
+					// see https://github.com/spring-cloud/spring-cloud-commons/issues/571
+					if (getNeverRefreshable().contains(bean.getClass().getName())) {
+						return false; // ignore
+					}
 					this.applicationContext.getAutowireCapableBeanFactory()
 							.destroyBean(bean);
 					this.applicationContext.getAutowireCapableBeanFactory()
@@ -115,6 +121,14 @@ public class ConfigurationPropertiesRebinder
 		return false;
 	}
 
+	@ManagedAttribute
+	public Set<String> getNeverRefreshable() {
+		String neverRefresh = this.applicationContext.getEnvironment().getProperty(
+				"spring.cloud.refresh.never-refreshable",
+				"com.zaxxer.hikari.HikariDataSource");
+		return StringUtils.commaDelimitedListToSet(neverRefresh);
+	}
+
 	@ManagedAttribute
 	public Set<String> getBeanNames() {
 		return new HashSet<>(this.beans.getBeanNames());

spring-cloud-context/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -41,6 +41,12 @@
 			"type": "java.util.Set<java.lang.String>",
 			"description": "Additional class names for beans to post process into refresh scope.",
 			"defaultValue": true
+		},
+		{
+			"name": "spring.cloud.refresh.never-refreshable",
+			"type": "java.lang.String",
+			"description": "Comma separated list of class names for beans to never be refreshed or rebound.",
+			"defaultValue": true
 		}
 	]
 }

spring-cloud-context/src/test/java/org/springframework/cloud/autoconfigure/RefreshAutoConfigurationTests.java

@@ -16,6 +16,8 @@
 
 package org.springframework.cloud.autoconfigure;
 
+import java.util.concurrent.atomic.AtomicInteger;
+
 import org.junit.Rule;
 import org.junit.Test;
 
@@ -30,6 +32,7 @@ import org.springframework.cloud.context.refresh.ContextRefresher;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Configuration;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.BDDAssertions.then;
 
 /**
@@ -68,8 +71,9 @@ public class RefreshAutoConfigurationTests {
 	public void refreshables() {
 		try (ConfigurableApplicationContext context = getApplicationContext(
 				WebApplicationType.NONE, Config.class, "config.foo=bar",
-				"spring.cloud.refresh.refreshable:" + ConfigProps.class.getName())) {
-			context.getBean(ConfigProps.class);
+				"spring.cloud.refresh.refreshable:"
+						+ SealedConfigProps.class.getName())) {
+			context.getBean(SealedConfigProps.class);
 			context.getBean(ContextRefresher.class).refresh();
 		}
 	}
@@ -77,23 +81,37 @@ public class RefreshAutoConfigurationTests {
 	@Test
 	public void extraRefreshables() {
 		try (ConfigurableApplicationContext context = getApplicationContext(
-				WebApplicationType.NONE, Config.class, "config.foo=bar",
+				WebApplicationType.NONE, Config.class, "sealedconfig.foo=bar",
 				"spring.cloud.refresh.extra-refreshable:"
-						+ ConfigProps.class.getName())) {
-			context.getBean(ConfigProps.class);
+						+ SealedConfigProps.class.getName())) {
+			context.getBean(SealedConfigProps.class);
 			context.getBean(ContextRefresher.class).refresh();
 		}
 	}
 
+	@Test
+	public void neverRefreshable() {
+		try (ConfigurableApplicationContext context = getApplicationContext(
+				WebApplicationType.NONE, Config.class, "countingconfig.foo=bar",
+				"spring.cloud.refresh.never-refreshable:"
+						+ CountingConfigProps.class.getName())) {
+			CountingConfigProps configProps = context.getBean(CountingConfigProps.class);
+			context.getBean(ContextRefresher.class).refresh();
+			assertThat(configProps.count)
+					.as("config props was rebound when it should not have been")
+					.hasValue(1);
+		}
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@EnableAutoConfiguration(exclude = DataSourceAutoConfiguration.class)
-	@EnableConfigurationProperties(ConfigProps.class)
+	@EnableConfigurationProperties({ SealedConfigProps.class, CountingConfigProps.class })
 	static class Config {
 
 	}
 
-	@ConfigurationProperties("config")
-	static class ConfigProps {
+	@ConfigurationProperties("sealedconfig")
+	static class SealedConfigProps {
 
 		private String foo;
 
@@ -113,4 +131,22 @@ public class RefreshAutoConfigurationTests {
 
 	}
 
+	@ConfigurationProperties("countingconfig")
+	static class CountingConfigProps {
+
+		private final AtomicInteger count = new AtomicInteger();
+
+		private String foo;
+
+		public String getFoo() {
+			return this.foo;
+		}
+
+		public void setFoo(String foo) {
+			count.incrementAndGet();
+			this.foo = foo;
+		}
+
+	}
+
 }