ai: apply changes for #1006 (1 review thread)

Addresses:
  - #4418708511 at src/databricks/sql/parameters/native.py:724

Signed-off-by: peco-engineer-bot[bot] <peco-engineer-bot[bot]@users.noreply.github.com>

Author: peco-engineer-bot[bot]

src/databricks/sql/parameters/native.py

@@ -728,6 +728,9 @@ def __init__(
             # DECIMAL can never have scale > precision, so this can only be a call
             # written for the old convention: keep it working for now (swap the
             # arguments) but warn so callers migrate before this becomes an error.
+            # scale == precision is deliberately *not* handled here: it reads the
+            # same under both conventions, so it gets the SQL meaning and is widened
+            # like any correctly ordered call (documented in the CHANGELOG).
             warnings.warn(
                 "DecimalParameter received scale ({}) > precision ({}); interpreting the "
                 "arguments using the legacy (swapped) convention as DECIMAL({},{}). "

tests/unit/test_parameters.py

@@ -214,6 +214,17 @@ def test_decimal_correct_order_with_more_fractional_digits_is_widened():
     assert p._cast_expr() == "DECIMAL(6,4)"
 
 
+def test_decimal_scale_equal_to_precision_is_widened_without_warning():
+    """scale == precision means the same in both conventions, so it is not treated as
+    a legacy call: it gets the SQL meaning and is widened like any correctly ordered
+    call (earlier releases bound DECIMAL(2,2) and rounded to 0.12). See CHANGELOG."""
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        p = DecimalParameter(Decimal("0.1234"), scale=2, precision=2)
+    assert not p._legacy_swapped
+    assert p._cast_expr() == "DECIMAL(4,4)"
+
+
 @pytest.mark.parametrize(
     "scale,precision,match",
     (