GH-9878: Fix ConcurrentModificationException in SpringIntegrationTestExecutionListener

    Fixes: gh-9878

    * return new list in MockIntegrationContext.getAutoStartupCandidates()

Signed-off-by: Alexander Hain <[email protected]>

Author: clf-ahain

spring-integration-test/src/main/java/org/springframework/integration/test/context/MockIntegrationContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2024 the original author or authors.
+ * Copyright 2017-2025 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.
@@ -111,7 +111,7 @@ public void afterSingletonsInstantiated() {
 	}
 
 	List<AbstractEndpoint> getAutoStartupCandidates() {
-		return this.autoStartupCandidates;
+		return new ArrayList<>(this.autoStartupCandidates);
 	}
 
 	/**

spring-integration-test/src/test/java/org/springframework/integration/test/context/MockIntegrationContextTests.java

@@ -0,0 +1,44 @@
+package org.springframework.integration.test.context;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.dsl.IntegrationFlow;
+import org.springframework.integration.dsl.context.IntegrationFlowContext;
+import org.springframework.integration.endpoint.AbstractEndpoint;
+import org.springframework.integration.gateway.MessagingGatewaySupport;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+
+@SpringJUnitConfig
+@ContextConfiguration(classes = MockIntegrationContextTests.Config.class)
+@SpringIntegrationTest
+public class MockIntegrationContextTests {
+	@Test
+	void springIntegrationTestExecutionListenerShouldNotFailWithConcurrentModificationException() {
+	}
+
+	@Configuration
+	@EnableIntegration
+	public static class Config {
+		@Bean
+		public AbstractEndpoint registerOnStopEndpoint(IntegrationFlowContext integrationFlowContext) {
+			return new AbstractEndpoint() {
+				@Override
+				protected void doStart() {
+					MessagingGatewaySupport gateway = new MessagingGatewaySupport() {
+					};
+					integrationFlowContext.registration(IntegrationFlow.from(gateway).get()).register();
+				}
+
+				@Override
+				protected void doStop() {
+					MessagingGatewaySupport gateway = new MessagingGatewaySupport() {
+					};
+					integrationFlowContext.registration(IntegrationFlow.from(gateway).get()).register();
+				}
+			};
+		}
+	}
+}