Fix NPE in ConnectionFactory when nested REQUIRES_NEW transaction establishes no JDBC connections

[Copilot]

ConnectionFactory.notify() throws NPE when a REQUIRES_NEW transaction nested within a REQUIRED transaction completes without establishing any JDBC connections.

Root Cause

When a transaction establishes no connections, concurrentHashMap.get(xid) returns null. Line 150 attempts to iterate over connectionProxyMap.values() without checking for null:

for (ConnectionProxy connectionProxy : connectionProxyMap.values()) {
    // NPE when connectionProxyMap is null
}

Changes

• ConnectionFactory.notify(): Added null check before accessing connectionProxyMap

  Map<String, ConnectionProxy> connectionProxyMap = concurrentHashMap.get(xid);
  if (connectionProxyMap == null) {
      return;
  }

• Test Coverage: Added NonDatabaseConnectionService and NoConnectionService to reproduce the scenario where an outer REQUIRED transaction has JDBC connections but inner REQUIRES_NEW does not

Scenario

@DSTransactional(propagation = DsPropagation.REQUIRED)
public void outerRequiredWithConnection() {
    // Establishes JDBC connection
    runQuery();
    // Nested REQUIRES_NEW with no JDBC operations
    innerService.businessLogicOnly();  // Previously threw NPE on commit
}

@DSTransactional(propagation = DsPropagation.REQUIRES_NEW)
public void businessLogicOnly() {
    // No database operations - pure business logic
}

Warning

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Original prompt

---

This section details on the original issue you should resolve

<issue_title>REQUIRED中嵌套REQUIRES_NEW时，满足一定条件必定报错"connectionProxyMap" is null</issue_title>
<issue_description>Describe the bug
REQUIRED中嵌套REQUIRES_NEW时，若REQUIRED中存在jdbc连接，但REQUIRES_NEW中不存在jdbc连接，必定触发报错"connectionProxyMap" is null
注：不论是通过注解DSTransactional还是TransactionalTemplate，都会有这个问题

To Reproduce
本人使用的版本：4.3.1

      <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>dynamic-datasource-spring-boot3-starter</artifactId>
        <version>4.3.1</version>
      </dependency>

复现代码：

@SpringBootTest
class NonTransactionTests {
    
    @Autowired
    NonDatabaseConnectionService nonDatabaseConnectionService;
    
    /**
     * 复现问题
     */
    @Test
    void test1() {
        nonDatabaseConnectionService.reProduce();
    }
    
}

import com.baomidou.dynamic.datasource.annotation.DSTransactional;
import com.baomidou.dynamic.datasource.tx.DsPropagation;
import com.ideaaedi.zoo.example.springboot.dynamic.datasource.mapper.MysqlStudentMapper;
import jakarta.annotation.Resource;
import org.springframework.aop.framework.AopContext;
import org.springframework.stereotype.Component;

import java.util.concurrent.ThreadLocalRandom;

@Component
public class NonDatabaseConnectionService {
    
    @Resource
    private MysqlStudentMapper mysqlStudentMapper;
    
    /**
     * 问题复现
     */
    @DSTransactional(propagation = DsPropagation.REQUIRED)
    public void reProduce() {
        triggerJdbcConnection();
        // 获取aop对象，确保bizLogic的aop生效
        ((NonDatabaseConnectionService) AopContext.currentProxy()).bizLogic();
    }
    
    /**
     * 触发jdbc连接
     */
    public void triggerJdbcConnection() {
        /*
         * 调试时发现，只有当触发了jdbc connection时，dynamic-datasource才会往ConnectionFactory.CONNECTION_HOLDER中放置事务连接信息
         */
        mysqlStudentMapper.list();
    }
    
    /**
     * 业务逻辑（模拟：满足某些业务条件时，可能不会有任何与数据库有关的操作）
     */
    @DSTransactional(propagation = DsPropagation.REQUIRES_NEW)
    public void bizLogic() {
        if (ThreadLocalRandom.current().nextBoolean()) {
            /*
             * bug反馈：如果代码走到这个if中，那么就会报错:
             *
             * java.lang.NullPointerException: Cannot invoke "java.util.Map.values()" because "connectionProxyMap" is null
             *
             * 	at com.baomidou.dynamic.datasource.tx.ConnectionFactory.notify(ConnectionFactory.java:150)
             * 	at com.baomidou.dynamic.datasource.tx.LocalTxUtil.commit(LocalTxUtil.java:91)
             * 	at com.baomidou.dynamic.datasource.tx.TransactionalTemplate.doExecute(TransactionalTemplate.java:126)
             * 	at com.baomidou.dynamic.datasource.tx.TransactionalTemplate.execute(TransactionalTemplate.java:94)
             * 	at com.baomidou.dynamic.datasource.aop.DynamicLocalTransactionInterceptor.invoke(DynamicLocalTransactionInterceptor.java:59)
             * 	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
             */
            System.err.println("bizLogic");
        } else {
            triggerJdbcConnection();
        }
    }
}

Expected behavior
期望如果方法不涉及jdbc操作的话，一切正常，不报错NPE

Screenshots

Desktop (please complete the following information):

• OS: WINDOWS10

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Additional context

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes REQUIRED中嵌套REQUIRES_NEW时，满足一定条件必定报错"connectionProxyMap" is null #763

---

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[Copilot]

Pull request overview

This PR addresses an NPE scenario in the dynamic datasource local transaction lifecycle when a REQUIRES_NEW transactional method performs no JDBC work, and adds an integration test reproduction to prevent regressions.

Changes:

• Add a guard in ConnectionFactory.notify(...) to safely handle transactions with no tracked JDBC connections.
• Introduce two Spring test services to reproduce the “REQUIRES_NEW without JDBC connection” case.
• Add a Spring Boot 3 starter test that exercises the outer REQUIRED + inner REQUIRES_NEW (no JDBC) flow.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
dynamic-datasource-test-common/.../NonDatabaseConnectionService.java	Adds a test helper service that opens a JDBC connection in an outer REQUIRED transaction and invokes an inner REQUIRES_NEW method.
dynamic-datasource-test-common/.../NoConnectionService.java	Adds a test helper service with a REQUIRES_NEW method that performs no JDBC operations.
dynamic-datasource-spring/.../ConnectionFactory.java	Adds a null-guard to avoid NPE when committing/rolling back a transaction that never obtained a JDBC connection.
dynamic-datasource-spring-boot3-starter/.../DsTransactionalTest.java	Adds an integration test covering the new edge case.

[Copilot]

Avoid writing to stdout from this Spring @service. It will add noisy console output to the test suite (and potentially to any app that happens to include test-common). Prefer removing the print entirely or using the project’s logger (e.g., Slf4j) if you need an observable side-effect.

Suggested change

System.out.println("Business logic without database operations");