Cypher: WHERE pattern-predicate AND order sensitivity with varlen clauses

[lmeyerov]

Summary

Direct-Cypher WHERE clauses with conjoined pattern predicates can produce different results depending on operand order when variable-length predicates are involved.

Repro (minimal)

Using a graph with:

• REL1 chain: a->b->c->d
• REL2 edges: a->e, b->e

Query A:

MATCH (n)
WHERE (n)-[:REL1*2]->() AND (n)-[:REL2*1]->()
RETURN n.id AS id ORDER BY id

Observed: [{"id": "b"}]

Query B (same operands swapped):

MATCH (n)
WHERE (n)-[:REL2*1]->() AND (n)-[:REL1*2]->()
RETURN n.id AS id ORDER BY id

Observed: []

Expected

AND should be order-invariant for logically equivalent predicates.

Context

• Discovered during Cypher multihop: expand direct variable-length support beyond endpoint-only patterns #973 amplification while hardening newly admitted bounded/exact varlen WHERE pattern support.
• Not used to block Cypher multihop: expand direct variable-length support beyond endpoint-only patterns #973 merge; tracked as follow-up correctness work.

Initial hypothesis

Lowering/evaluation for where-pattern rewrites may be order-sensitive when mixing multiple pattern predicates, likely around semi-apply marker/filter sequencing.