[BUG] Query with aggregates and GROUP BY works Azure Data Studio but generates an exception with spring-data-cosmos

[Blackbaud-JasonBodnar]

Describe the bug
The following query works in Azure Data Studio:

SELECT c.scs, c.bbid, CONCAT(c.scs, "-", c.microservice) AS scsMicroservice, COUNT(1), SUM(c.totalCharacters) FROM c WHERE c.scs != null GROUP BY c.scs, c.bbid, CONCAT(c.scs, "-", c.microservice)

But when used with @Query() on a method in a CosmosRepository it generates an exception

Exception or Stack Trace

java.lang.IllegalArgumentException: Entity is null.
	at org.springframework.util.Assert.notNull(Assert.java:172)
	at com.azure.spring.data.cosmos.core.convert.MappingCosmosConverter.readInternal(MappingCosmosConverter.java:94)
	at com.azure.spring.data.cosmos.core.convert.MappingCosmosConverter.read(MappingCosmosConverter.java:79)
	at com.azure.spring.data.cosmos.core.CosmosTemplate.toDomainObject(CosmosTemplate.java:1303)
	at com.azure.spring.data.cosmos.core.CosmosTemplate.emitOnLoadEventAndConvertToDomainObject(CosmosTemplate.java:1299)
	at com.azure.spring.data.cosmos.core.CosmosTemplate.lambda$runQuery$35(CosmosTemplate.java:1157)
	at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:106)
	at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79)
	at reactor.core.publisher.FluxFlatMap$FlatMapMain.drainLoop(FluxFlatMap.java:713)
	at reactor.core.publisher.FluxFlatMap$FlatMapMain.drain(FluxFlatMap.java:589)
	at reactor.core.publisher.FluxFlatMap$FlatMapInner.onSubscribe(FluxFlatMap.java:956)
	at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:201)
	at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:83)
	at reactor.core.publisher.Flux.subscribe(Flux.java:8642)
	at reactor.core.publisher.FluxFlatMap$FlatMapMain.onNext(FluxFlatMap.java:427)
	at reactor.core.publisher.FluxPublishOn$PublishOnSubscriber.runAsync(FluxPublishOn.java:440)
	at reactor.core.publisher.FluxPublishOn$PublishOnSubscriber.run(FluxPublishOn.java:527)
	at reactor.core.scheduler.WorkerTask.call(WorkerTask.java:84)
	at reactor.core.scheduler.WorkerTask.call(WorkerTask.java:37)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:840)
	Suppressed: java.lang.Exception: #block terminated with an error
		at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:100)
		at reactor.core.publisher.Mono.block(Mono.java:1742)
		at com.azure.spring.data.cosmos.core.CosmosTemplate.runQuery(CosmosTemplate.java:1159)
		at com.azure.spring.data.cosmos.repository.support.StringBasedCosmosQuery.execute(StringBasedCosmosQuery.java:108)
		at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:170)
		at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:158)
		at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:164)
		at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:143)
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
		at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:70)
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)
		at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97)
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184)

To Reproduce
Steps to reproduce the behavior:

1. Create a ComsosRepository with an @Query() method.
2. Call the method.

Code Snippet

@Query(value =
    "SELECT c.scs, c.bbid, CONCAT(c.scs, \"-\", c.microservice) AS scsMicroservice, COUNT(1), SUM(c.totalCharacters) FROM c WHERE c.scs != null GROUP BY c.scs, c.bbid, CONCAT(c.scs, \"-\", c.microservice)"
    )
List<Object> getStatistics();

Expected behavior
The query does not cause an excpetion.

Setup (please complete the following information):

• Library/Libraries: com.azure:azure-spring-data-cosmos:5.14.0
• Java version: 17
• Frameworks: Spring Boot

Information Checklist
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• [ X ] Repro Steps Added
• [ X ] Setup information Added

[github-actions]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @kushagraThapar @pjohari-ms @TheovanKraay.

[kushagraThapar]

@trande4884 can you please take a look at this issue, thanks!

[trande4884]

@Blackbaud-JasonBodnar it does seem we have a gap in Dynamic Projection. Although return type of List is not allowed Spring does allow for List<Object[]> however that does not currently work in azure-spring-data-cosmos either. However it is not an ideal way of doing things and the preferred way is using interface projection, see section 4 in this article. Supporting dynamic projection is a larger task that we will have to plan for and I will update here with further information. Thank you for bringing this issue to our attention!

[kushagraThapar]

@trande4884 curious if this is planned in our upcoming semester?

[trande4884]

Yes we can plan this for the upcoming semester, I will start taking a look!