[coverage] Conformance findings: METADATA-035,STATEMENT-023

先查看 tests/ 下的 coverage PR diff，尤其是 test_get_tables_empty_table_types_filter_matches_all 和 test_failed_statement_error_carries_sql_state，接著追蹤對應的 Thrift backend 路徑。重現針對不存在資料表的 SQL 陳述式，並比較 Thrift 與 kernel backend。完成的標準是兩個預期失敗測試都通過：空的 table_types 符合所有類型，且失敗的陳述式會以預期的錯誤文字揭露 SQLSTATE 42P01。

Summary

Surfaced by the multi-language coverage fan-out while conformance-testing these SPEC-IDs against databricks/databricks-sql-python. Each finding is committed as an expected-failure (xfail) test in the coverage PR — the test asserts the CORRECT (post-fix) behavior and stays red until THIS driver (databricks/databricks-sql-python) is fixed, then flips green as a tripwire.

Findings

• METADATA-035 [thrift]: Thrift backend forwards an empty getTables table_types list verbatim as TGetTablesReq(tableTypes=[]), so the server treats it as match-none and returns zero rows instead of behaving like None (match all types); the kernel backend correctly normalises [] to None
  • failing test: test_get_tables_empty_table_types_filter_matches_all (see the coverage PR diff under tests/)
• STATEMENT-023 [thrift]: Thrift backend drops the server SQLSTATE on a FAILED statement: it builds exceptions from errorMessage/displayMessage only and never copies TStatus.sqlState / TGetOperationStatusResp.sqlState, so no PEP 249 error attribute carries 42P01 for TABLE_OR_VIEW_NOT_FOUND; the kernel backend does forward sql_state
  • failing test: test_failed_statement_error_carries_sql_state (see the coverage PR diff under tests/)

Reproduce & Expected

STATEMENT-023 — Validates that when the server resolves a statement to a FAILED state, the driver surfaces the server's SQLSTATE on the raised error — not just a free-text message. A statement whose SQLSTATE is stable and server-assigned is used: a reference to a table that does not exist, which Databricks reports as TABLE_OR_VIEW_NOT_FOUND with SQLSTATE 42P01. The raised error must expose that SQLSTATE through the driver's standard error surface (ADBC AdbcException.SqlState, JDBC SQLException.getSQLState(), DBAPI error attributes, ODBC SQLGetDiagRec SQLSTATE, etc.). This pins the portable half of the cross-protocol error contract: consumers branch on the status/SQLSTATE pair, so both protocols must populate it identically even though each raises its own natural concrete exception class. The CONCRETE exception TYPE is deliberately NOT asserted — it legitimately differs per protocol and per driver (the reference driver raises DatabricksException on SEA and HiveServer2Exception on Thrift), so requiring one class would encode a driver-internal detail rather than the contract.

Reproduce:

SELECT * FROM nonexistent_catalog_xyz123.nonexistent_schema.nonexistent_table

Expected (per the shared spec):

• full assertion contract:

result:
- error:
    sql_state: 42P01
- error:
    contains:
    - TABLE_OR_VIEW_NOT_FOUND
    - not found
    - cannot be found

Context

• The behavior was first fixed in a DIFFERENT driver — reference PR: https://github.com/adbc-drivers/databricks/pull/604 — which seeded the shared language-neutral spec. This issue tracks the same conformance gap in databricks/databricks-sql-python; the reference PR is for cross-referencing the intended behavior, NOT a change to this repo.
• Coverage PR carrying the reproducing xfail test(s): https://github.com/databricks/databricks-driver-test/pull/1072