From c03d95d501927e226fe36094d6ef4c0f1fb9de2f Mon Sep 17 00:00:00 2001
From: Matthew Roeschke <10647082+mroeschke@users.noreply.github.com>
Date: Wed, 6 Sep 2023 13:52:36 -0700
Subject: [PATCH] Raise TypeError for any non-parseable argument in to_datetime

---
 python/cudf/cudf/core/tools/datetimes.py | 16 ++++++++--------
 python/cudf/cudf/tests/test_datetime.py  |  6 ++++++
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/python/cudf/cudf/core/tools/datetimes.py b/python/cudf/cudf/core/tools/datetimes.py
index a759f9dc3e1..f736e055163 100644
--- a/python/cudf/cudf/core/tools/datetimes.py
+++ b/python/cudf/cudf/core/tools/datetimes.py
@@ -294,12 +294,8 @@ def to_datetime(
 def _process_col(col, unit, dayfirst, infer_datetime_format, format):
     if col.dtype.kind == "M":
         return col
-    elif col.dtype.kind == "m":
-        raise TypeError(
-            f"dtype {col.dtype} cannot be converted to {_unit_dtype_map[unit]}"
-        )
 
-    if col.dtype.kind in ("f"):
+    elif col.dtype.kind in ("f"):
         if unit not in (None, "ns"):
             factor = cudf.Scalar(
                 column.datetime._unit_to_nanoseconds_conversion[unit]
@@ -325,8 +321,9 @@ def _process_col(col, unit, dayfirst, infer_datetime_format, format):
             )
         else:
             col = col.as_datetime_column(dtype="datetime64[ns]")
+        return col
 
-    if col.dtype.kind in ("i"):
+    elif col.dtype.kind in ("i"):
         if unit in ("D", "h", "m"):
             factor = cudf.Scalar(
                 column.datetime._unit_to_nanoseconds_conversion[unit]
@@ -340,6 +337,7 @@ def _process_col(col, unit, dayfirst, infer_datetime_format, format):
             )
         else:
             col = col.as_datetime_column(dtype=_unit_dtype_map[unit])
+        return col
 
     elif col.dtype.kind in ("O"):
         if unit not in (None, "ns") or col.null_count == len(col):
@@ -364,11 +362,13 @@ def _process_col(col, unit, dayfirst, infer_datetime_format, format):
                 format = column.datetime.infer_format(
                     element=col.element_indexing(0)
                 )
-            col = col.as_datetime_column(
+            return col.as_datetime_column(
                 dtype=_unit_dtype_map[unit],
                 format=format,
             )
-    return col
+    raise TypeError(
+        f"dtype {col.dtype} cannot be converted to {_unit_dtype_map[unit]}"
+    )
 
 
 def get_units(value):
diff --git a/python/cudf/cudf/tests/test_datetime.py b/python/cudf/cudf/tests/test_datetime.py
index 4a4e9b67c2e..4c20258ae67 100644
--- a/python/cudf/cudf/tests/test_datetime.py
+++ b/python/cudf/cudf/tests/test_datetime.py
@@ -2156,3 +2156,9 @@ def test_format_timezone_not_implemented(code):
         cudf.to_datetime(
             ["2020-01-01 00:00:00 UTC"], format=f"%Y-%m-%d %H:%M:%S %{code}"
         )
+
+
+@pytest.mark.parametrize("arg", [True, False])
+def test_args_not_datetime_typerror(arg):
+    with pytest.raises(TypeError):
+        cudf.to_datetime([arg])