NPE during transaction rollback when custom query fails [DATAGRAPH-997]

[spring-projects-issues]

Konstantin Lutovich opened DATAGRAPH-997 and commented

Hello,

I'm facing an issue where Neo4jTransactionManager fails to rollback transaction after runtime exception in a custom Cypher query. Attached github repository contains a project to reproduce the problem.

It contains a repository which extends GraphRepository and adds a single method with a custom query MATCH (m:Movie) WHERE m.title = '' RETURN m AS movie, 10/0 AS other. This query obviously generates a "division by zero" runtime exception. However I can also see NPE stacktrace. It seems to occur because Neo4jTransactionManager tries to rollback transaction that has already been rolled back by OGM code in BoltResponse#next().

Division by zero in this example is artificial, in reality queries can fail in many different ways at runtime (deadlocks, type errors, etc.).

Seen stacktrace:

Exception in thread "main" java.lang.NullPointerException
at org.springframework.data.neo4j.transaction.Neo4jTransactionManager.doRollback(Neo4jTransactionManager.java:275)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processRollback(AbstractPlatformTransactionManager.java:853)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.rollback(AbstractPlatformTransactionManager.java:830)
at org.springframework.transaction.interceptor.TransactionAspectSupport.completeTransactionAfterThrowing(TransactionAspectSupport.java:522)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:286)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:656)
at org.neo4j.services.MovieService$$EnhancerBySpringCGLIB$$b8f1a8e3.findByTitle(<generated>)
at org.neo4j.SampleMovieApplication.main(SampleMovieApplication.java:30)

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Affects: 4.2.3 (Ingalls SR3)

Reference URL: https://github.com/lutovich/sdn-test

Referenced from: commits 2a4df87, 1e39f81

Backported to: 4.2.8 (Ingalls SR8)