Cypher/GFQL WHERE cannot mix generic row predicates with pattern predicates

[lmeyerov]

Problem

Current local Cypher/GFQL validation rejects WHERE clauses that mix a generic row predicate with a pattern predicate in the same boolean expression.

Current measured error:

[unsupported-cypher-query] Cypher WHERE pattern predicates cannot yet be mixed with generic row expressions

Benchmark Impact

This is now benchmark-backed from pyg-bench on current master 14dafaf6b951954d8de840f9236f3e874249ebac.

Official LDBC SNB Interactive lane:

• interactive-complex-10 / common-interest-score
• artifact: /home/lmeyerov/Work/pyg-bench/results/runs/dgx-spark-snb-interactive-ic10-origin-master-14dafaf6b9-fresh-r1
• direct Cypher: primitive_gap
• GFQL: workaround-backed partial under #880

Minimal Shape

MATCH (person:Person {id: $personId})-[:KNOWS*2..2]-(friend),
      (friend)-[:IS_LOCATED_IN]->(city:City)
WHERE NOT friend=person AND
      NOT (friend)-[:KNOWS]-(person)
RETURN friend.id

The important part is the mixed WHERE condition:

• generic row expression: NOT friend=person
• pattern predicate: NOT (friend)-[:KNOWS]-(person)

Why This Matters

This is a real official benchmark blocker on current master, not just a parser nicety:

• exact-2-hop recommendation shapes are common benchmark work
• the official query is otherwise staged and measurable in the benchmark harness
• the failure happens before direct execution, so it blocks clean benchmark coverage for the direct Cypher path

Expected Direction

Support mixed WHERE boolean expressions that combine:

• generic row comparisons / equality predicates
• pattern predicates

without forcing the benchmark harness to rewrite the official query into a non-faithful form.

Related

• benchmark coverage meta issue: #992
• residual GFQL workaround umbrella: #880
• benchmark artifact: /home/lmeyerov/Work/pyg-bench/results/runs/dgx-spark-snb-interactive-ic10-origin-master-14dafaf6b9-fresh-r1

[lmeyerov]

Confirmed still reproducible on pin cd707f0 (0.54.0, 2026-04-06, sf1):

• Run: pyg-bench dgx-spark-ic10-rebaseline-2026-04-06
• Status: primitive_gap, latency 153ms (fast fail at validation)
• Error: [unsupported-cypher-query] Cypher WHERE pattern predicates cannot yet be mixed with generic row expressions
• GFQL workaround (expand 1..2-hop + local scoring): partial, 1272ms

The ic10 probe is now in the runner with proper issue_ref tracking. The #880 GFQL workaround is the current floor for IC10.