Decided the payload shape: a map with camelCase keys, fields in declared
order, every optional field always present and nil when absent - never
omitted. C#'s [MessagePackObject]/[Key("name")] map formatter already does
this by default (confirmed byte-for-byte below); Rust's `to_vec_named`
encoding for these four types used `skip_serializing_if = "Option::is_none"`,
which omits the key instead - the gap the map cited ("C# writes nine fields
with nils, Rust omits absent ones").
Removes skip_serializing_if from Edge, RawDocumentHeader,
SelectionDocumentRecord and SelectionPage, keeping #[serde(default)] for
decode-side robustness. Selection (the request type) is untouched - out of
this ruling's scope, and the map already confirmed the request side agrees
between runtimes.
Adds tests/selection_wire_parity.rs: RawDocumentHeader and Edge, each
carrying several absent optionals, encoded via to_vec_named and compared
byte-for-byte against hex captured from a real MessagePack C# 3.1.7 run
(same pattern as error_message.rs's csharp_hex vectors) - both now agree
exactly.
What is NOT done, and why: R-AP also called for "Select gains projection,
so the thing the vectors test is the thing that decides." In C#, projection
(header vs document, ToRawRecord/ToEdge/FromRecord) is owned entirely by
CultNetDocumentRegistry.SelectPage/SelectAll (GameCult.Networking), not by
CultNetSelectionEvaluator.Select/Page - the evaluator returns raw Rows/
EdgeMatches and knows nothing about a document's payload serializer, which
only the registry's bindings own. Moving page assembly into the evaluator
without threading a caller-supplied serializer (the same pattern ordinalOf/
shardIdOf already use) would give a schema-generic evaluator per-binding
wire knowledge it should not own; threading a serializer callback in is
buildable but changes SelectPage/SelectAll's own signature and every
caller, plus the parity-vector harness's construction - a materially larger
change than this pass's remaining scope. No vector yet exercises the real
CultNetSnapshotResponseRawV1Message/select_page output byte-for-byte; only
the two nested wire types in isolation. Flagged for the operator per the
brief's own stop condition.
R-AQ, updated: type-level byte parity for the nested wire shapes (Edge,
RawDocumentHeader) is now real and vector-tested. Whole-message byte parity
for cultnet.snapshot_response_raw.v1 is still not - the smaller claim (this
cut's page bytes agree only where R-AH's fixed-shape rule reaches, and
projection ownership is still split between the evaluator and the registry)
is the true one until "Select gains projection" actually lands.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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