[coverage] Conformance findings: METADATA-035

从 tests/ 下 coverage PR 中失败的测试 test_get_tables_empty_table_types_filter_matches_all 开始，然后跟踪 Python connector 的 Thrift get_tables 路径。根据链接的 conformance context 确认空 table_types 的行为；测试通过且空 types 与所有 table types 匹配即表示完成。

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 get_tables forwards an empty table_types list verbatim as TGetTablesReq.tableTypes=[], so the server matches no table type and returns 0 rows, instead of treating empty like None (match all) per the hiveserver2 empty-types parity contract; the connector's kernel path already normalises [] to None.
  • failing test: test_get_tables_empty_table_types_filter_matches_all (see the coverage PR diff under tests/)

Context

• The behavior was first fixed in a DIFFERENT driver — reference PR: https://github.com/databricks/databricks-sql-kernel/pull/183 — 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/1021