Fix meta calculation for to_datetime (#1153)

dask_expr/_collection.py

@@ -6192,6 +6192,8 @@ def to_datetime(arg, meta=None, **kwargs):
             meta = meta_series_constructor(arg)([pd.Timestamp("2000", **tz_kwarg)])
             meta.index = meta.index.astype(arg.index.dtype)
             meta.index.name = arg.index.name
+    else:
+        meta = make_meta(meta)
 
     kwargs.pop("infer_datetime_format", None)
 

dask_expr/_expr.py

@@ -1461,6 +1461,10 @@ class ToDatetime(Elemwise):
     _defaults = {"kwargs": None}
     _keyword_only = ["kwargs", "meta"]
 
+    @functools.cached_property
+    def _meta(self):
+        return self.operand("meta")
+
     @staticmethod
     def operation(*args, **kwargs):
         return get_meta_library(args[0]).to_datetime(*args, **kwargs)

dask_expr/tests/test_collection.py

@@ -815,6 +815,14 @@ def test_abs_errors():
     pytest.raises((TypeError, NotImplementedError), lambda: ddf.abs())
 
 
+def test_to_datetime_timezone():
+    pdf = pd.DataFrame({"a": ["2023-04-01 22:12:11.932417+00:00"]})
+    df = from_pandas(pdf)
+    df["a"] = to_datetime(df.a, format="ISO8601", meta=("a", "datetime64[ns, UTC]"))
+    pdf["a"] = to_datetime(pdf.a, format="ISO8601")
+    assert_eq(df, pdf)
+
+
 def test_to_datetime():
     pdf = pd.DataFrame({"year": [2015, 2016], "month": [2, 3], "day": [4, 5]})
     df = from_pandas(pdf, npartitions=2)