I found a discrepancy when running two semantically equivalent queries against an empty database:

1:

CREATE ()<-[:A]-()
RETURN 0 AS n0
	UNION

MATCH ()
CALL { CREATE () RETURN 0 AS n2 SKIP 1 }
RETURN 1 AS n0

Produces:

+----+
| n0 |
+----+
|  0 |
+----+

2:

CREATE ()<-[:A]-()
RETURN 0 AS n0
	UNION
CALL { RETURN 0 AS n1 }
MATCH ()
CALL { CREATE () RETURN 0 AS n2 SKIP 1 }
RETURN 1 AS n0

Produces:

+----+
| n0 |
+----+
|  0 |
|  1 |
+----+

I believe the queries mentioned above are semantically equivalent and thus their result should be the same.

I encountered this issue when testing queries on the FalkorDB master branch in a Docker container running redis:7.2.3-bookworm.

Steps to reproduce

Run the aforementioned, semantically equivalent, queries against an empty database and observe that their results differ.

Expected behavior

The queries should result in the same behavior

Actual behavior

The query results differ