ConfigurationPropertiesRebinder exposes invalid state racily

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

@@ -196,11 +196,16 @@ private boolean rebind(String name, ApplicationContext appContext) {
 		return false;
 	}
 
+	public static boolean skipReset = false;
+
 	/**
 	 * Reset bean properties to their class-level defaults so that removed properties do
 	 * not retain stale values after rebinding.
 	 */
 	private void resetBeanToDefaults(Object bean) {
+		if (skipReset) {
+			return;
+		}
 		Class<?> targetClass = AopUtils.getTargetClass(bean);
 		if (!hasDefaultConstructor(targetClass)) {
 			// Beans that have no default constructor (for example constructor-bound beans

spring-cloud-context/src/test/java/org/springframework/cloud/context/properties/ConfigurationPropertiesRebinderLifecycleIntegrationTests.java

@@ -16,11 +16,15 @@
 
 package org.springframework.cloud.context.properties;
 
+import org.assertj.core.api.AtomicBooleanAssert;
 import org.junit.jupiter.api.Test;
 
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -36,6 +40,9 @@
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.test.annotation.DirtiesContext;
 
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.BDDAssertions.then;
 
 @SpringBootTest(classes = TestConfiguration.class)
@@ -50,6 +57,45 @@ public class ConfigurationPropertiesRebinderLifecycleIntegrationTests {
 	@Autowired
 	private ConfigurableEnvironment environment;
 
+	@ParameterizedTest
+	@ValueSource(booleans = { true, false })
+	void racy_properties(boolean skipReset) throws Exception {
+		ConfigurationPropertiesRebinder.skipReset = skipReset;
+		int violations = 0;
+		var run = new AtomicBoolean(true);
+
+		// message is not null at start of test
+		then(this.properties.getMessage()).isEqualTo("Hello scope!");
+
+		// run the test for 1 second
+		new Thread(() -> {
+			try {
+				Thread.sleep(1000);
+			} catch (InterruptedException e) {
+				throw new RuntimeException(e);
+			} finally {
+				run.set(false);
+			}
+		}).start();
+
+		// a thread calls rebind() in a loop
+		new Thread(() -> {
+			while (run.get()) {
+				rebinder.rebind();
+			}
+		}).start();
+
+		// read the properties in a loop
+		while (run.get()) {
+			String message = properties.getMessage();
+			// we expect that message is never null as we don't change the properties
+			if (message == null) {
+				violations++;
+			}
+		}
+		assertThat(violations).isEqualTo(0);
+	}
+
 	@Test
 	@DirtiesContext
 	public void testRefresh() {