[coverage] Conformance findings: FEATUREFLAG-001 #984

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

• FEATUREFLAG-001 [sea]: SEA/kernel session open calls FeatureFlagResolver::prepare_for_session_open() unconditionally before CreateSession, emitting one connector-service feature-flag GET even with telemetry disabled and no flag consumer (the typed readers are still dead_code); the fetch should be lazy so an unconsumed flag context costs no request
  • failing test: test_no_feature_flag_request_when_flags_are_unconsumed (see the coverage PR diff under tests/)

Reproduce & Expected

FEATUREFLAG-001 — Opens a proxied connection with telemetry explicitly disabled and runs SELECT 1.

Reproduce:

SELECT 1 AS value

Expected (per the shared spec):

• result has exactly 1 row(s)
• col 0, row 0 == 1 (type Int32)
• full assertion contract:

result:
- row_count: 1
- column:
    index: 0
    row: 0
    type: Int32
    equals: 1
protocol:
  thrift:
  - http_request_count:
      path_prefix: /api/2.0/connector-service/feature-flags/
      expected: 0
  sea:
  - http_request_count:
      path_prefix: /api/2.0/connector-service/feature-flags/
      expected: 0

Context

• The behavior was first fixed in a DIFFERENT driver — reference PR: feat(feature-flags): generalize driver-side cache databricks-sql-go#496 — 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/1820