fix: Correct REST JSON serialization of UUID/HUGEINT/BLOB/BIT (#89)#92
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Type-coverage audit follow-up. Several scalar types were mis-routed in the REST serializer: - UUID -> read via the VARCHAR path (as a string pointer) but is physically a 128-bit int, causing a SEGFAULT on any UUID column. Now formatted as the canonical 8-4-4-4-12 hex string. - HUGEINT/UHUGEINT -> read as 64-bit ints, truncating values and mis-striding multi-row chunks (e.g. MAX::HUGEINT -> -1). Now emitted as exact decimal strings (lossless; JSON numbers lose precision above 2^53). - BLOB -> emitted raw bytes (invalid UTF-8 / invalid JSON). Now uses DuckDB's blob string form (printable as-is, others as \xNN). - BIT -> emitted raw bit storage as garbage. Now emitted as its 0/1 string. All honor row validity (NULL -> null). Adds [scalar_types] regression tests. VARINT/BIGNUM, GEOMETRY and VARIANT remain serialized as null (internal/extension encodings not safely convertible at the vector level) — documented as a known limitation. Found via type audit + codex review.
This was referenced Jun 27, 2026
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Summary
Follow-up to #90 / #91. A full audit of every DuckDB type against the REST JSON serializer turned up more mis-routed scalar types — including a crash:
UUID8-4-4-4-12hex stringHUGEINT/UHUGEINTMAX::HUGEINT→-1)BLOB\xNNfor non-printable)BIT"101010"string128-bit integers are emitted as strings (per maintainer decision) so values beyond 2⁶³ survive — JSON numbers lose precision above 2⁵³.
Verified correct (no change needed)
All standard scalars,
DATE/TIME/TIMESTAMP(+variants),DECIMAL,ENUM,INTERVAL,JSON, and the nested typesLIST/STRUCT/ARRAY/UNION/MAPincl. deeply nested combinations.Known limitation
VARINT/BIGNUM,GEOMETRY, andVARIANTstill serialize asnull— their internal/extension encodings aren't safely convertible at the vector level. Documented in code;to_json(col)remains a workaround.Test plan
[query_executor][scalar_types]regression tests: UUID (single + multi-row, no crash), HUGEINT/UHUGEINT exact decimals, BLOB, BIT, and NULLs.Relates to #89