feat(cypher): support comma-separated MATCH patterns (cartesian product) #990

Summary

MATCH (n), (m) RETURN n.num, m.num used to fail with:

GFQLValidationError: Comma-separated Cypher MATCH patterns are only supported...

That gap blocked comma-separated node-only MATCH cartesian products, including TCK scenarios like match1-5, return4-9, and parts of the shortest-path benchmark family.

Status

Resolved on April 2, 2026 by PR #1019.

What landed:

• direct Cypher lowering/runtime support for disconnected comma-separated node-only MATCH cartesian products
• row/runtime support for node-only rows(binding_ops=...)
• coverage for scalar projection, row filters, aggregates, whole-row projection, WITH, and ORDER BY

Context

PR #986 added multi-alias scalar RETURN for connected single-hop patterns (MATCH (a)-[:R]->(b) RETURN a.id, b.id). Cartesian products (MATCH (n), (m)) are a different shape because there is no edge connecting the aliases, so the implementation needs a node-set cross join rather than an edge-backed bindings table.

Related

• Direct Cypher row lowering rejects scalar multi-alias projections from a single MATCH #981: multi-alias scalar RETURN for connected patterns
• AST row select cannot reference edge alias properties after traversal #982: edge alias property access
• feat(cypher): implement shortestPath execution with igraph/cugraph backends #1010: now unblocked by this landing
• PR feat(cypher): support comma-separated node-only MATCH #1019: implementation and regression coverage