UnknownError in a DuplicatedSlotKey

[DominicWuest]

When running the following query:

UNWIND 0 AS n0
RETURN null AS n1
	UNION
MATCH ()
OPTIONAL MATCH ()-[n2]->(n3)--(n4)-[aZvD]->(n5)
OPTIONAL MATCH
	(:!n6)-[{y:0, y:aZvD.x, x:0, x:0}]->(ex),
	(),
	({x:0, y:0}),
	()<--(),
	()
RETURN null AS n1

I encountered the following error:

Neo4jError: Neo.DatabaseError.General.UnknownError ((DuplicatedSlotKey(RuntimeKey(aZvDy,PropertyKeyName(x),RELATIONSHIP_TYPE),2),RefSlot(2,false,Any)) (of class scala.Tuple2))

I believe the query mentioned above is semantically and syntactically correct and thus no error should be thrown here.

I encountered this issue when testing queries against the Neo4j 5.18.0 community version in a Docker container running alpine v.3.
When testing the query against the enterprise version, no error is thrown, unless the slotted runtime is forced.

Steps to reproduce

Run the following queries and observe it throws an error:

UNWIND 0 AS n0 RETURN null AS n1 UNION MATCH () OPTIONAL MATCH ()-[n2]->(n3)--(n4)-[aZvD]->(n5) OPTIONAL MATCH (:!n6)-[{y:0, y:aZvD.x, x:0, x:0}]->(ex), (), ({x:0, y:0}), ()<--(), () RETURN null AS n1

Expected behavior

The query should run successfully

Actual behavior

The query fails with the error message Neo4jError: Neo.DatabaseError.General.UnknownError ((DuplicatedSlotKey(RuntimeKey(aZvDy,PropertyKeyName(x),RELATIONSHIP_TYPE),2),RefSlot(2,false,Any)) (of class scala.Tuple2))

[LinneaAndersson]

@DominicWuest Thanks for reporting this bug, I was able to reproduce it.

We will have a look at the issue and get back to you once we have more information