[rjb32]

Implement a point property type.

[rjb32]

Note

AI-generated summary.

Summary

Goal. Add Neo4j's point as a stored property type, so CREATE (:City {at: point({longitude: 2.3522, latitude: 48.8566})}) stores a point and RETURN n.at reads back point({x: 2.3522, y: 48.8566, crs: 'wgs-84'}).

Approach. ValueType::Point and CellTag::Point are appended before their sentinels. db::Point is 32 trivially copyable bytes: x, y, z as doubles, a one-byte PointCRS (cartesian, cartesian-3d, wgs-84, wgs-84-3d) and zeroed padding. The constructor makes equal points equal in every byte, so dumps, EncodedList comparisons and DISTINCT keys compare raw bytes. point(map) follows Neo4j's PointValue.fromInputFields. The type is threaded through storage, dump/load, the v3 dialects (!storage.point, db.to_point), the binary protocol (POINT = 22), Python and npm.

Where to look.

• storage/metadata/Point.h:36 Point: the layout and its invariants
• storage/metadata/Point.cpp:263 Point::Point: validation, longitude wrap, -0.0 normalisation
• storage/metadata/Point.cpp:453 Point::fromMap: the point() key rules
• storage/dump/PropertyContainerDumpConstants.h:23: the static_asserts pinning the on-disk layout
• storage/CellOrder.cpp:33 CellOrderClass: points sort after paths and before datetimes, as in Neo4j

point({longitude, latitude[, height]})   wgs-84 / wgs-84-3d
point({x, y[, z]})                       cartesian / cartesian-3d
point({..., crs: 'wgs-84'}) | srid: 4326 explicit CRS; both raises
null map or null value                   null
non-finite, latitude past 90, wrong dimension, string coordinate   raises
longitude past 180                       wrapped

Evidence

• Before: main has no point function and no point property type.
  After:

  test_query_ir_point_property          [  PASSED  ] 36 tests.
  test_query_ir_point_value_flow        [  PASSED  ] 17 tests.   CASE, coalesce, UNION, joins, MERGE, map projection
  test_storage_point                    [  PASSED  ] 9 tests.
  test_storage_dump_point_graph         [  PASSED  ] 3 tests.    nodes, edges, lists and maps of points
  test_storage_dump_propertydumpformat  pointDumpBytes hash pinned, deterministic over two runs
  test_storage_dump_celltagdumpformat   listAndMapHoldingAPointOfEveryCRS hash pinned
  test_net_turing_proto_roundtrip       [  PASSED  ] 40 tests.   RoundTripsPointColumnsAcrossChunkSizes
  wasm/npm client_smoke.mjs             passed: ..., points
  ctest                                 100% tests passed, 0 tests failed out of 1164
  

  Checked by hand against a server: BinaryClient returns Point(srid=7203, x=1.0, y=2.0, z=None), and the npm client returns {"srid":4979,"x":3,"y":4,"z":5}.

Merge Danger

Door: one-way

ValueType::Point = 11, CellTag::Point = 14, the PointCRS ordinals and the 32-byte layout go into every datapart written from now on, and POINT = 22 into the wire protocol.

Blast Radius: storage

Every switch over ValueType and CellTag gains a case. Clients older than this one cannot decode a POINT column.