Recreate the scoped proxy of a changed @Configuration bean

plugin/hotswap-agent-spring-plugin/src/main/java/org/hotswap/agent/plugin/spring/reload/SpringBeanReload.java

@@ -461,17 +461,46 @@ private void refreshChangedBeans(SpringBeanReloadContext context, Consumer<List<
         }
     }
 
+    private static final String SCOPED_TARGET_NAME_PREFIX = "scopedTarget.";
+
     private void resetConfigurationBeanDefinition(Set<String> configurationBeansToReload) {
         for (String beanName : beanFactory.getBeanDefinitionNames()) {
+            if (!beanFactory.containsBeanDefinition(beanName)) {
+                // already removed, e.g. a scoped proxy
+                continue;
+            }
             BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanName);
             String factoryBeanName = beanDefinition.getFactoryBeanName();
             if (factoryBeanName != null && configurationBeansToReload.contains(factoryBeanName)) {
                 LOGGER.debug("the bean '{}' will be recreating because the factory bean '{}' is changed", beanName, factoryBeanName);
                 beanFactory.removeBeanDefinition(beanName);
+                removeScopedProxyDefinition(beanName);
             }
         }
     }
 
+    /**
+     * A scoped proxy @Bean (e.g. @SessionScope) is registered as "scopedTarget.name" with the factory method and as
+     * "name" for the proxy. If only the target is removed, the proxy definition stays and the @Configuration class is
+     * not processed for this @Bean again, so "scopedTarget.name" is missing. Remove the proxy too.
+     */
+    private void removeScopedProxyDefinition(String targetBeanName) {
+        // ScopedProxyUtils.TARGET_NAME_PREFIX, spring-aop is not a dependency of the plugin
+        if (!targetBeanName.startsWith(SCOPED_TARGET_NAME_PREFIX)) {
+            return;
+        }
+        String proxyBeanName = targetBeanName.substring(SCOPED_TARGET_NAME_PREFIX.length());
+        if (!beanFactory.containsBeanDefinition(proxyBeanName)) {
+            return;
+        }
+        BeanDefinition proxyDefinition = beanFactory.getBeanDefinition(proxyBeanName);
+        PropertyValue targetBeanNameValue = proxyDefinition.getPropertyValues().getPropertyValue("targetBeanName");
+        if (targetBeanNameValue != null && targetBeanName.equals(targetBeanNameValue.getValue())) {
+            LOGGER.debug("the scoped proxy '{}' of bean '{}' will be recreated too", proxyBeanName, targetBeanName);
+            beanFactory.removeBeanDefinition(proxyBeanName);
+        }
+    }
+
     private void refreshNewBean(SpringBeanReloadContext context) {
         for (BeanDefinitionHolder beanDefinitionHolder : context.newScanBeanDefinitions) {
             BeanDefinitionReaderUtils.registerBeanDefinition(beanDefinitionHolder, beanFactory);

plugin/hotswap-agent-spring-plugin/src/test/java/org/hotswap/agent/plugin/spring/scopedproxy/ScopedProxyBeanTest.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2013-2026 the HotswapAgent authors.
+ *
+ * This file is part of HotswapAgent.
+ *
+ * HotswapAgent is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * HotswapAgent is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with HotswapAgent. If not, see http://www.gnu.org/licenses/.
+ */
+package org.hotswap.agent.plugin.spring.scopedproxy;
+
+import org.hotswap.agent.plugin.spring.BaseTestUtil;
+import org.hotswap.agent.plugin.spring.ClassSwappingRule;
+import org.hotswap.agent.plugin.spring.reload.SpringChangedAgent;
+import org.hotswap.agent.plugin.spring.scopedproxybak.ScopedProxyConfigurationBak;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.context.support.AbstractApplicationContext;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Change of a @Configuration class with a scoped proxy @Bean (#393).
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = ScopedProxyTestConfiguration.class)
+public class ScopedProxyBeanTest {
+
+    @Rule
+    public ClassSwappingRule swappingRule = new ClassSwappingRule();
+
+    @Autowired
+    private AbstractApplicationContext applicationContext;
+
+    @Before
+    public void before() {
+        BaseTestUtil.configMaxReloadTimes();
+        DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) applicationContext.getBeanFactory();
+        SpringChangedAgent.getInstance(beanFactory);
+        swappingRule.setBeanFactory(beanFactory);
+    }
+
+    @After
+    public void after() {
+        SpringChangedAgent.destroyBeanFactory((DefaultListableBeanFactory) applicationContext.getBeanFactory());
+    }
+
+    @Test
+    public void changeConfigurationWithScopedProxyBean() throws Exception {
+        assertEquals("aaaa", applicationContext.getBean(WebUser.class).web());
+        assertEquals("plain-a", applicationContext.getBean("plainBean"));
+        // a proxy kept by someone else, it looks up the target by name
+        WebCls oldProxy = applicationContext.getBean("webCls", WebCls.class);
+
+        swappingRule.swapClasses(ScopedProxyConfiguration.class, ScopedProxyConfigurationBak.class, 1);
+
+        // the scoped target was "No bean named 'scopedTarget.webCls' available" before
+        assertEquals("aaaa", applicationContext.getBean(WebUser.class).web());
+        assertEquals("aaaa", oldProxy.getWeb());
+        // a new scope (another thread here, a new session in a web application) uses the changed @Bean method
+        assertEquals("bbbb", inNewThread(() -> applicationContext.getBean(WebUser.class).web()));
+        assertEquals("plain-b", applicationContext.getBean("plainBean"));
+
+        // and back again
+        swappingRule.swapClasses(ScopedProxyConfiguration.class, ScopedProxyConfiguration.class, 2);
+        assertEquals("aaaa", applicationContext.getBean(WebUser.class).web());
+        assertEquals("aaaa", inNewThread(() -> applicationContext.getBean(WebUser.class).web()));
+        assertEquals("plain-a", applicationContext.getBean("plainBean"));
+    }
+
+    private static String inNewThread(java.util.concurrent.Callable<String> callable) throws Exception {
+        AtomicReference<Object> result = new AtomicReference<>();
+        Thread thread = new Thread(() -> {
+            try {
+                result.set(callable.call());
+            } catch (Throwable e) {
+                result.set(e);
+            }
+        });
+        thread.start();
+        thread.join();
+        if (result.get() instanceof Throwable) {
+            throw new AssertionError("failed in new thread", (Throwable) result.get());
+        }
+        return (String) result.get();
+    }
+}

plugin/hotswap-agent-spring-plugin/src/test/java/org/hotswap/agent/plugin/spring/scopedproxy/ScopedProxyConfiguration.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2013-2026 the HotswapAgent authors.
+ *
+ * This file is part of HotswapAgent.
+ *
+ * HotswapAgent is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * HotswapAgent is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with HotswapAgent. If not, see http://www.gnu.org/licenses/.
+ */
+package org.hotswap.agent.plugin.spring.scopedproxy;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
+
+/**
+ * Like @SessionScope, with a thread scope instead of the session. Without @Qualifier: with it, the context does not
+ * start with the agent on Spring 5.3, see setCacheBeanMetadata(false) in SpringPlugin and #603.
+ */
+@Configuration
+public class ScopedProxyConfiguration {
+    @Bean
+    @Scope(scopeName = "thread", proxyMode = ScopedProxyMode.TARGET_CLASS)
+    public WebCls webCls() {
+        WebCls cls = new WebCls();
+        cls.setWeb("aaaa");
+        return cls;
+    }
+
+    @Bean
+    public String plainBean() {
+        return "plain-a";
+    }
+}

plugin/hotswap-agent-spring-plugin/src/test/java/org/hotswap/agent/plugin/spring/scopedproxy/ScopedProxyTestConfiguration.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2013-2026 the HotswapAgent authors.
+ *
+ * This file is part of HotswapAgent.
+ *
+ * HotswapAgent is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * HotswapAgent is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with HotswapAgent. If not, see http://www.gnu.org/licenses/.
+ */
+package org.hotswap.agent.plugin.spring.scopedproxy;
+
+import org.springframework.beans.factory.config.CustomScopeConfigurer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.SimpleThreadScope;
+
+@Configuration
+@ComponentScan(basePackageClasses = WebUser.class)
+public class ScopedProxyTestConfiguration {
+    @Bean
+    public static CustomScopeConfigurer threadScope() {
+        CustomScopeConfigurer configurer = new CustomScopeConfigurer();
+        configurer.addScope("thread", new SimpleThreadScope());
+        return configurer;
+    }
+}

plugin/hotswap-agent-spring-plugin/src/test/java/org/hotswap/agent/plugin/spring/scopedproxy/WebCls.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2013-2026 the HotswapAgent authors.
+ *
+ * This file is part of HotswapAgent.
+ *
+ * HotswapAgent is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * HotswapAgent is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with HotswapAgent. If not, see http://www.gnu.org/licenses/.
+ */
+package org.hotswap.agent.plugin.spring.scopedproxy;
+
+public class WebCls {
+    private String web;
+
+    public String getWeb() {
+        return web;
+    }
+
+    public void setWeb(String web) {
+        this.web = web;
+    }
+}

plugin/hotswap-agent-spring-plugin/src/test/java/org/hotswap/agent/plugin/spring/scopedproxy/WebUser.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2013-2026 the HotswapAgent authors.
+ *
+ * This file is part of HotswapAgent.
+ *
+ * HotswapAgent is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * HotswapAgent is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with HotswapAgent. If not, see http://www.gnu.org/licenses/.
+ */
+package org.hotswap.agent.plugin.spring.scopedproxy;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class WebUser {
+    @Autowired
+    private WebCls webCls;
+
+    public String web() {
+        return webCls.getWeb();
+    }
+}

plugin/hotswap-agent-spring-plugin/src/test/java/org/hotswap/agent/plugin/spring/scopedproxybak/ScopedProxyConfigurationBak.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2013-2026 the HotswapAgent authors.
+ *
+ * This file is part of HotswapAgent.
+ *
+ * HotswapAgent is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * HotswapAgent is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with HotswapAgent. If not, see http://www.gnu.org/licenses/.
+ */
+package org.hotswap.agent.plugin.spring.scopedproxybak;
+
+import org.hotswap.agent.plugin.spring.scopedproxy.WebCls;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
+
+@Configuration
+public class ScopedProxyConfigurationBak {
+    @Bean
+    @Scope(scopeName = "thread", proxyMode = ScopedProxyMode.TARGET_CLASS)
+    public WebCls webCls() {
+        WebCls cls = new WebCls();
+        cls.setWeb("bbbb");
+        return cls;
+    }
+
+    @Bean
+    public String plainBean() {
+        return "plain-b";
+    }
+}