orneryd / NornicDB / 36384799038

87%

Build Type

push

github

Committed by orneryd

Commit Message

fix(cypher): optional shortestPath and shortestPath-as-value converge on one BFS (#581, #721)

OPTIONAL MATCH p = shortestPath(...) previously rewrote the clause to a
plain MATCH and swallowed every error into a fabricated {"result": null}
row with the wrong columns. Clause-only and anchored forms
(MATCH (a) OPTIONAL MATCH p = shortestPath((a)-...->(c))) now run the
shared shortestPath BFS with left-outer-join semantics: one row per seed,
projected values when a path exists, nulls when none, errors propagated.

shortestPath(...)/allShortestPaths(...) are now valid in value position
(RETURN length(shortestPath((a)-[:R*]->(b))), WITH, SET projections):
the projected-pattern validator masks the path-function arguments instead
of rejecting them, and the shared row evaluator runs the same BFS per row.
length() of an unbound path returns null instead of a fabricated 0.

Convergence: MATCH, OPTIONAL MATCH, and value forms all traverse through
e.shortestPath/e.allShortestPaths and project through buildPathContext;
clause-position detection shares extractShortestPathCall with
isShortestPathClause (new); the validator's mask reuses indexASCIIFold
(zero-alloc ASCII fold shared with equalFoldASCII).

Performance (M2 Max, -cpu=1 -count=3, BenchmarkStatementRouting):
  autocommit/simple_match_limit  main 161 allocs, 17.4-18.8 us/op
                                 branch 161 allocs, 17.5-17.7 us/op
  explicit_tx/simple_match_limit main 88 allocs, 11.5-12.0 us/op
                                 branch 88 allocs, 11.4 us/op
  No allocation or latency regression; extractShortestPathCall's
  upperASCII(funcName) copies were removed with constant upper-case
  literals after memprofile diffing showed the +2 allocs they added.

Tests: optional_shortest_path_test.go pins #581's five Neo4j outcomes
plus value forms in RETURN/WITH, autocommit and explicit transactions,
each run twice; full pkg/cypher suite, -race, and TCK ratchet
(7794/7794, 100%) pass.

Coverage Stats

249 of 322 new or added lines in 7 files covered. (77.33%)

14 existing lines in 3 files now uncovered.

175899 of 202287 relevant lines covered (86.96%)

1.02 hits per line