[Bug] hll_* errors surface as Comet errors instead of HLL_INVALID_INPUT_SKETCH_BUFFER / HLL_UNION_DIFFERENT_LG_K #7549

Describe the bug

When the native HLL expressions fail, Comet raises a plain Comet execution error instead of Spark's SparkRuntimeException with the HLL error condition. Both engines fail on the same inputs, but the error class, SQLSTATE and message differ.

native/common/src/error.rs SparkError has no HLL variant, so these errors cannot reach SparkErrorConverter / ShimSparkErrorConverter.

Steps to reproduce

SELECT hll_sketch_estimate(X'0102030405');

Spark 4.x raises [HLL_INVALID_INPUT_SKETCH_BUFFER] Invalid call to hll_sketch_estimate; only valid HLL sketch buffers are supported as inputs ... with SQLSTATE 22546. Comet raises a Comet execution error with a different message.

Expected behavior

Comet raises the same error condition and SQLSTATE as Spark. A likely fix, following #5072 :

• add SparkError variants for the two conditions in native/common/src/error.rs;
• map them in the spark-4.x ShimSparkErrorConverter to QueryExecutionErrors.hllInvalidInputSketchBuffer(function) and QueryExecutionErrors.hllUnionDifferentLgK(left, right, function);
• cover them with expect_error_class SQL tests or checkSparkError.

Additional context

Surfaced by the HLL audit for #7396 . The comparison experiment confirmed both engines fail on the same inputs ( #7396 (comment) ). The serdes currently list this as an incompatible reason that is never returned; the audit PR moves it to a compatibility note that links here.

Willingness to contribute

I can contribute a fix for this bug independently