BUG: Frequency shift on empty DataFrame (#60172)

* freq shift

* Save local changes before merging

Author: eightyseven

doc/source/whatsnew/v3.0.0.rst

@@ -772,6 +772,7 @@ Other
 - Bug in :meth:`DataFrame.eval` and :meth:`DataFrame.query` which caused an exception when using NumPy attributes via ``@`` notation, e.g., ``df.eval("@np.floor(a)")``. (:issue:`58041`)
 - Bug in :meth:`DataFrame.eval` and :meth:`DataFrame.query` which did not allow to use ``tan`` function. (:issue:`55091`)
 - Bug in :meth:`DataFrame.query` which raised an exception or produced incorrect results when expressions contained backtick-quoted column names containing the hash character ``#``, backticks, or characters that fall outside the ASCII range (U+0001..U+007F). (:issue:`59285`) (:issue:`49633`)
+- Bug in :meth:`DataFrame.shift` where passing a ``freq`` on a DataFrame with no columns did not shift the index correctly. (:issue:`60102`)
 - Bug in :meth:`DataFrame.sort_index` when passing ``axis="columns"`` and ``ignore_index=True`` and ``ascending=False`` not returning a :class:`RangeIndex` columns (:issue:`57293`)
 - Bug in :meth:`DataFrame.transform` that was returning the wrong order unless the index was monotonically increasing. (:issue:`57069`)
 - Bug in :meth:`DataFrame.where` where using a non-bool type array in the function would return a ``ValueError`` instead of a ``TypeError`` (:issue:`56330`)

pandas/core/frame.py

@@ -5705,7 +5705,7 @@ def shift(
                 "Passing a 'freq' together with a 'fill_value' is not allowed."
             )
 
-        if self.empty:
+        if self.empty and freq is None:
             return self.copy()
 
         axis = self._get_axis_number(axis)

pandas/tests/frame/methods/test_shift.py

@@ -747,3 +747,13 @@ def test_shift_axis_one_empty(self):
         df = DataFrame()
         result = df.shift(1, axis=1)
         tm.assert_frame_equal(result, df)
+
+    def test_shift_with_offsets_freq_empty(self):
+        # GH#60102
+        dates = date_range("2020-01-01", periods=3, freq="D")
+        offset = offsets.Day()
+        shifted_dates = dates + offset
+        df = DataFrame(index=dates)
+        df_shifted = DataFrame(index=shifted_dates)
+        result = df.shift(freq=offset)
+        tm.assert_frame_equal(result, df_shifted)