[coverage] Conformance findings: STATEMENT-025

Start with the STATEMENT-025 xfail test in the coverage PR diff under tests/ and trace the driver’s per-operation CloseOperation teardown path. Reproduce the two-query case, then verify that a failed close does not escape teardown or prevent connection reuse, while the expected row counts and protocol calls still hold.

Summary

Surfaced by the multi-language coverage fan-out while conformance-testing these SPEC-IDs against databricks/databricks-sql-nodejs. 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-nodejs) is fixed, then flips green as a tripwire.

Findings

• STATEMENT-025 [thrift]: Thrift: a failed per-operation teardown close (CloseOperation forced to 404) is not best-effort — the 404 propagates out of teardown as a raw THTTPException instead of being swallowed, so cleanup becomes a caller-visible error
  • failing test: STATEMENT-025 — failed teardown CloseOperation is swallowed and teardown continues [thrift] (see the coverage PR diff under tests/)

Reproduce & Expected

STATEMENT-025 — Validates that a FAILING per-operation close RPC issued during teardown is BEST EFFORT: the failure must not propagate out of close/dispose, and must not abort the rest of teardown.

Reproduce:

SELECT id FROM range(1000)
SELECT 1

Expected (per the shared spec):

• result has exactly 1000 row(s)
• completes without an exception
• completes without an exception
• result has exactly 1 row(s)
• full assertion contract:

result:
- label: consumed
  row_count: 1000
- label: teardown
  no_exception: true
- label: reused_connection
  no_exception: true
- label: reused_connection
  row_count: 1
protocol:
  thrift:
  - call_min:
      method: CloseOperation
      min: 1
  sea:
  - call_min:
      operation: CloseStatement
      min: 1

Context

• The behavior was first fixed in a DIFFERENT driver — reference PR: https://github.com/adbc-drivers/databricks/pull/618 — which seeded the shared language-neutral spec. This issue tracks the same conformance gap in databricks/databricks-sql-nodejs; 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/1225