orneryd / NornicDB / 30023243756

89%

main: 89%

Build Type

Pull #265

github

Committed by local

Commit Message

feat(cypher): support every OPTIONAL MATCH and aggregate shape, mirroring Neo4j

Replace the remaining shape rejections in the traversal-seeded OPTIONAL
MATCH pipeline with full support, mapped from Neo4j's Cypher runtime
(community/cypher in the neo4j/neo4j source):

- A clause that shares no variable with earlier clauses is a valid
  disconnected optional join, not an error. It now evaluates with
  Apply + Optional semantics (ApplyPipe.scala / OptionalPipe.scala):
  the pattern is enumerated once, each left row joins with candidates,
  and a row with no match is preserved with newly-introduced variables
  bound to null.
- Single-node patterns are supported: a bound variable introduces no
  new bindings and preserves rows whether or not the pattern holds; an
  unbound variable is an independent scan with the same left-outer
  contract.
- Multi-hop chains and pre-bound relationship variables route through
  the same general Apply + Optional path with identity agreement on
  shared variables. The connected single-hop fast path keeps
  OptionalExpandAll semantics (null seeds propagate null bindings).
- Aggregation supports every shape instead of erroring: stdev/stdevp
  implement StdevFunction.scala's contract (null on empty, 0.0 for a
  single value, sample vs population divisors); RETURN items that
  contain aggregates inside larger expressions (count(x) + 1,
  coalesce(sum(w), 0)) are isolated, aggregated per group, and
  substituted into the outer expression exactly like the front-end
  isolateAggregation rewrite. The only remaining error is an empty
  aggregate argument list, which Neo4j itself rejects at compile time.

The branch is rebased onto main, dropping the earlier fail-loud
multi-clause guard commit entirely: no valid Cypher shape is rejected
anywhere in this pipeline.

New tests cover disconnected node and relationship patterns (join and
null-fill), bound single-node row preservation, multi-hop chains, mixed
aggregate expressions, and std... (continued)

Pull Request Pull Request #265: fix(cypher): evaluate traversal-seeded OPTIONAL MATCH projections (function projection, rel-var binding, chained clauses, aggregation)

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676 of 930 new or added lines in 5 files covered. (72.69%)

30 existing lines in 12 files now uncovered.

147250 of 165393 relevant lines covered (89.03%)

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