handle unnamed series input

Author: shobsi

bigframes/series.py

@@ -53,6 +53,7 @@
 import bigframes.core.block_transforms as block_ops
 import bigframes.core.blocks as blocks
 import bigframes.core.expression as ex
+import bigframes.core.guid as guid
 import bigframes.core.indexers
 import bigframes.core.indexes as indexes
 import bigframes.core.ordering as order
@@ -1200,12 +1201,20 @@ def dot(self, other):
         if len(other.columns.names) == 1:
             # Process single level columns in other
             # Let's leverage the DataFrame.dot
-            na_mask = other.isna().any()
-            self_as_row = self.to_frame().T
+            self_named = self
+            if self_named.name is None:
+                self_named = self.copy()
+                self_named.name = guid.generate_guid()
+
+            self_as_row = self_named.to_frame().T
             frame_dot_result_as_row = self_as_row.dot(other)
             frame_dot_result_as_col = frame_dot_result_as_row.T
-            series_dot_result = frame_dot_result_as_col[self.name]
+            series_dot_result = frame_dot_result_as_col[self_named.name]
+
+            # take care of the NA values
+            na_mask = other.isna().any()
             result = series_dot_result.mask(na_mask)
+            result.name = self.name
         else:
             # TODO: Remove this special code path after DataFrame.dot supports
             # multi-level columns.

tests/system/small/test_series.py

@@ -3195,6 +3195,29 @@ def test_dot_df_with_na(scalars_dfs):
     )
 
 
+def test_dot_df_unnamed(session):
+    ps = pd.Series([0, 1, 2, 3])
+    assert ps.name is None  # this is the scenario we are testing specifically
+
+    pdf = pd.DataFrame(
+        {"a": [-1, 2, -3, 4], "b": [-10, 20, -30, 40], "c": [-1, 2, -3, pd.NA]}
+    )
+
+    s = session.read_pandas(ps)
+    df = session.read_pandas(pdf)
+
+    pd_result = ps @ pdf
+    bf_result = s @ df
+
+    pd.testing.assert_series_equal(
+        bf_result.to_pandas(),
+        pd_result,
+        check_index_type=False,
+        check_dtype=False,
+        check_exact=False,
+    )
+
+
 @pytest.mark.parametrize(
     ("left", "right", "inclusive"),
     [