fix(date): import pandas locally in make_ts_exclusive (#5885)

Signed-off-by: Anas Khan <83116240+anxkhn@users.noreply.github.com>

Author: anxkhn

sqlmesh/utils/date.py

@@ -344,6 +344,8 @@ def make_exclusive(time: TimeLike) -> datetime:
 
 
 def make_ts_exclusive(time: TimeLike, dialect: DialectType) -> datetime:
+    import pandas as pd
+
     ts = to_datetime(time)
     if dialect == "tsql":
         return to_utc_timestamp(ts) - pd.Timedelta(1, unit="ns")

tests/utils/test_date.py

@@ -14,11 +14,13 @@
     is_categorical_relative_expression,
     is_relative,
     make_inclusive,
+    make_ts_exclusive,
     to_datetime,
     to_time_column,
     to_timestamp,
     to_ts,
     to_tstz,
+    to_utc_timestamp,
 )
 
 
@@ -141,6 +143,17 @@ def test_make_inclusive_tsql(start_in, end_in, start_out, end_out, dialect) -> N
     )
 
 
+def test_make_ts_exclusive() -> None:
+    # tsql subtracts 1ns from the UTC timestamp; must not raise NameError (pd not imported)
+    assert make_ts_exclusive("2020-01-01 12:00:00", dialect="tsql") == to_utc_timestamp(
+        to_datetime("2020-01-01 12:00:00")
+    ) - pd.Timedelta(1, unit="ns")
+    # non-tsql dialects add 1 microsecond
+    assert make_ts_exclusive("2020-01-01 12:00:00", dialect="duckdb") == to_datetime(
+        "2020-01-01 12:00:00.000001"
+    )
+
+
 @pytest.mark.parametrize(
     "expression, result",
     [