Query on a single-attribute key schema applies a condition on a non-key attribute to the sort key #674

On a key schema with one HASH and one RANGE attribute, the engine checks only that the key condition has an equality on the HASH attribute. A second clause on any other attribute reaches storage as the sort key condition, and the SQLite and PostgreSQL backends apply a sort key condition that names no RANGE attribute to the first RANGE column (crates/storage-sqlite/src/data/query_scan.rs:79 and crates/storage-postgres/src/data/query_scan.rs:162 on main; lines 90 and 190 on #429, which keeps the fallback). The query returns items whose sort key matches the value, and a value whose type differs from the sort key's answers 500.

Reproduction

main at 3051e50, dev builds with the SQLite and the PostgreSQL backend; both answer the same. Table key pk (S) and sk (N). GSI gsi with HASH h (S) and RANGE a (S), projection ALL. Two items:

• pk "p1", sk 4, h "o1", a "x", zz 9
• pk "p1", sk 5, h "o1", a "p1", zz 4

The first request filters on sk: it returns the item whose sk is 4, and the item whose zz is 4 has sk 5. The third filters on a, the index's RANGE attribute, and returns one of the two items with pk "p1". The last applies sk = "x" to a.

#429 adds a value type check on this path that reads the table's attribute definitions. On the #429 branch the last request answers 400 One or more parameter values were invalid: Condition parameter type does not match schema type, because the table defines sk as N, and the other four answer as on main. A clause on an attribute the table does not define, or one whose value has the defined type, still reaches storage. Once this path refuses non-key conditions, its type check can read the queried key schema's definitions only, as #429 does on a multi-attribute key schema.

Expected

ValidationException with Query condition missed key schema element: <RANGE attribute>, before the request reaches storage, whatever the value's type. Measured on the service on 2026-10-30 on a GSI with HASH GSI2PK (S) and RANGE GSI2SK (S) of a table keyed on PK (S): GSI2PK = :h AND PK = :k answers Query condition missed key schema element: GSI2SK with :k an S and with :k an N, two samples each. #489 has the base table form with a comparison, pk = :x AND z > :x, measured on 2026-10-23: the service answers Query condition missed key schema element: sk. On #429's branch the multi-attribute path refuses such a clause this way, naming the first RANGE attribute without a condition, and the service answers the same on multi-attribute key schemas (three shapes, 2026-10-30). The base table form with an equality (pk = :p AND zz = :v), a table with no RANGE attribute, and conditions with three or more clauses on a single-attribute key schema, where the service's condition count rule may answer first, were not measured and should be before the fix.