SpelEvaluator.evaluate(…) fails with NullPointerException when an expression yields a null value

[rogeriomgatto]

I'm trying to use SpEL to bind parameter values from DTOs like this, in a JDBC repository:

    @Query(" ........ :#{#route.timestamp} .......")
    fun updateRoute(driverId: UUID, route: Route): Instant?

When any property is null, an NPE is thown in org.springframework.data.repository.query.SpelEvaluator because it uses Collectors.toMap and it doesn't support null values.

Also, there is no convertion to database types, for example an Instant value isn't converted to java.sql.Timestamp and sql execution fails.

I managed to fix both issues locally (I think):

• In spring-data-commons
  • patched SpelEvaluator to gather TypeInformation using Expression::getValueTypeDescriptor
  • introduced a version of evaluate that returns a vo with both value and TypeInformation
  • got rid of the NPE by doing the collection manually instead of using Collectors.toMap
• In spring-data-jdbc:
  • patched StringBasedJdbcQuery to use the new method from SpelEvaluator
  • passed values and TypeInformation through convertAndAddParameter instead of adding directly to the MapSqlParameterSource

How should I proceed to send the PRs, since they involve two projects?

[mp911de]

Can you please provide a reproducer and attach the stack trace so we can better understand where the issue comes from?

[spring-projects-issues]

If you would like us to look at this issue, please provide the requested information. If the information is not provided within the next 7 days this issue will be closed.

[rogeriomgatto]

I have provided a test case in this repository: https://github.com/rogeriomgatto/minimal-test-case-1577

The following tests reproduce the bugs, the other tests are just to confirm everything else is ok:

• DemoApplicationTests#shouldInsertRouteInformationWithDTO fails with NPE because :#{#routeInfo.routeUuid} resolves to null
• DemoApplicationTests#shouldUpdateRouteInformationWithDTO fails because :#{#routeInfo.routeUuidLastModifiedDate} resolves to a java.time.Instant and postgres can't handle that type of parameter

I also uploaded my proposed fixes, and can provide pull requests, I just don't know how to proceed since one PR depends on the other. Should I just open them?

• Changes to SpelEvaluator in spring-data-commons
• Changes to StringBasedJdbcQuery in spring-data-jdbc

To test with the proposed changes, clone both repositories, checkout branch gh-1577-spring-data-relational, and mvn install. Uncomment the dependencyManagement blocks in minimal-test-case-1577 and run tests again, everything passes.

[rogeriomgatto]

Forgot the stack traces.

NPE.txt

BadSqlGrammarException.txt

[mp911de]

Thanks a lot. The problem is being caused by SpelEvaluator that resides in Spring Data Commons. Let me move this ticket to the right project and fix it there.

[mp911de]

Regarding the conversion issue, we never added conversion support to String-based queries. It would make sense to run binding values by the QueryMapper. Can you file a new ticket in Spring Data Relational?

[rogeriomgatto]

Thanks for the fix!

Regarding the conversion issue, we never added conversion support to String-based queries. It would make sense to run binding values by the QueryMapper. Can you file a new ticket in Spring Data Relational?

For string queries in general, there is conversion support when using "regular" parameter binding, just not for SpEL expressions, right? In my test cases, regular parameters of type java.time.Instant are properly converted before being sent to the database. Should I open the new issue as "Add conversion support for SpEL parameters in string queries"?

[mp911de]

Yes, please.