The consolidated branch now carries the log-callback forwarding
(log_callback.go references kernel_set_log_callback / kernel_log_callback),
so KERNEL_REV must point at a kernel revision that exports those symbols.
Bump from the tier2 rev 02c0a434 (pre-log-callback) to 946c263, the head of
kernel PR #169 (mani/c-abi-log-callback), which defines them. The kernel-lib
build resolves this unmerged SHA via its PR-head-ref fallback, so the tagged
kernel-backend build links a header carrying the symbols.

Temporary: re-pin to the squash-merge SHA once kernel #169 lands.

Co-authored-by: Isaac
Signed-off-by: Mani Kaustubh Mathur <mani.mathur@databricks.com>

Point KERNEL_REV at c19e5d1, the current head of kernel PR #169. The
prior pin (946c263) was an orphaned SHA from an earlier force-push of the
same PR branch. ABI version is unchanged (still 1 — the earlier bump was
reverted), and all driver-used C-ABI symbols are present in the header at
the new rev.

Co-authored-by: Isaac

Point KERNEL_REV at c19e5d1, the current head of kernel PR #169. The
prior pin (946c263) was an orphaned SHA from an earlier force-push of the
same PR branch. ABI version is unchanged (still 1 — the earlier bump was
reverted), and all driver-used C-ABI symbols are present in the header at
the new rev.

Co-authored-by: Isaac
Signed-off-by: Mani Kaustubh Mathur <mani.mathur@databricks.com>

Match the slimmed kernel PR (#169 → mTLS + ABI-version only): remove the
Go wiring for the C-ABI symbols dropped kernel-side, re-pin KERNEL_REV to
the updated kernel head (12919b3), and keep the two survivors.

Keep:
- WithKernelClientCertificate → set_tls_client_certificate (mTLS); the
  option, config plumbing, unit tests, and kernel_mtls_test.go hermetic
  handshake test all stay.
- checkABIVersion() / abiVersions() at connect (abi.go + abi_test.go +
  TestABIVersionMatches) — the drift handshake.

Remove (no merged consumer; kernel symbols gone):
- ctx-cancel bridge: cancel.go (ctxWatcher/cancelledErr), cancel_test.go,
  cancel_connect_test.go; revert OpenSession to plain kernel_session_open,
  rows.go nextBatch to plain kernel_result_stream_next_batch, and
  operation.go's execute-path wrap to its inline form.
- log-callback bridge: log_callback.go, logforward.go, logforward_test.go,
  and the TestLogCallback* cases; initKernelLogging reverts to the
  kernel_init_logging (stderr) path.
- CloudFetch toggle: WithKernelCloudFetch + the CloudFetchEnabled field and
  its validation/forwarding/classification (UseCloudFetch back to inert).
- close_blocking references (never wired; CloseSession stays fire-and-forget).

Reverted kernel_e2e_test.go to drop the three cancel-family e2e tests
(mid-fetch / query-cancel-during-execution / connect-honors-cancelled-ctx);
the pre-existing TestKernelE2ECancellation still covers query cancel.

Validated against the new kernel lib: untagged build/vet/tests green; tagged
build + vet + kernel-backend unit tests green; live e2e against a warehouse
green (Select1, DataTypes ×18, CloudFetch, Cancellation, M2M, TLSSkipVerify,
Interval, MetricViewMetadata — all PASS).

Co-authored-by: Isaac
Signed-off-by: Mani Kaustubh Mathur <mani.mathur@databricks.com>

Bring PR #409 up to date after #412 (SEA PuPr tail: proxy / retry / max-chunks /
telemetry) and #414 (ErrorCategory) landed on main. #409 and #412 both branched
off #399 and extend the same kernel option surface, so the merge conflicted on
8 files; every conflict is additive-vs-additive and resolved by keeping both
sides:

- KERNEL_REV — re-pin to the #169 kernel tip 760625b, the only rev that carries
  BOTH #169's symbols (mTLS set_tls_client_certificate + abi_version, which
  #409's own code links) AND #178's set_retry_config (which the merged-in #412
  code links). main's 9ac3f3d lacks the former; the old pin 12919b3 lacks the
  latter. 760625b = 12919b3's work + merged #178, same #169 lineage.
- internal/config/config.go, internal/backend/kernel/config.go, connector.go,
  doc.go, kernel_config.go — keep both option families (mTLS client cert from
  #409; proxy / retry-overall-timeout / max-chunks from #412). The connector
  reject message and the ProxyURL doc take main's forward-looking wording.
- kernel_test.go, kernel_experimental_test.go — de-interleave the spliced test
  additions (ABI-version test vs proxy/retry tests; disposition-map, option, and
  DeepCopy cases) into complete units, keeping every test from both.

Verified on BOTH build paths: default pure-Go (go build/test ./...) and tagged
(-tags databricks_kernel, linking the .a rebuilt at 760625b) — build, vet, and
the touched-package tests all green. TestKernelExperimentalFieldsClassified
passes, confirming no experimental field was dropped in the merge.

Co-authored-by: Isaac
Signed-off-by: Mani Kaustubh Mathur <mani.mathur@databricks.com>

The kernel-backend CI job started failing after this branch re-pinned KERNEL_REV
onto the #169 lineage that carries #178's configurable retry policy (5 attempts,
1s..60s backoff, 900s budget), which is now honored on the kernel path via
WithRetries.

The hermetic TLS tests (kernel_mtls_test.go) assert the TLS/mTLS handshake
OUTCOME against a local httptest server. Their negative cases (handshake must
fail: no client cert, untrusted CA, hostname mismatch) drive a connect that is
meant to fail — and now retry it with escalating backoff. kernel_session_open is
a blocking cgo call that cannot observe the Go ctx cancel mid-retry (a tracked
deferral), so runKernelConnect's query goroutine outlived the test by ~34s per
negative case and eventually wrote to the torn-down test pipe → "signal: broken
pipe", failing the root package.

Add WithRetries(-1, 0, 0) — the idiomatic disable form, honored on the kernel
path — to runKernelConnect so a deliberately-failing connect settles after a
single attempt. The whole file now runs in ~0.15s (was tens of seconds per
negative case). No production code change; only the test's connect options.

Co-authored-by: Isaac
Signed-off-by: Mani Kaustubh Mathur <mani.mathur@databricks.com>