REGR: fix recursion error in GeoDataFrame constructor with MultiIndex (#2497)

* REGR: fix recursion error in GeoDataFrame constructor with MultiIndex

* Add test for pivot (GH-2057)

* add changelog

Co-authored-by: Matt Richards <45483497+m-richards@users.noreply.github.com>

CHANGELOG.md

@@ -15,6 +15,10 @@ Deprecations and compatibility notes:
 
 Bug fixes:
 
+- Fix regression (RecursionError) in reshape methods such as ``unstack()``
+  and ``pivot()`` involving MultiIndex, or GeoDataFrame construction with
+  MultiIndex (#2486).
+
 Notes on (optional) dependencies:
 
 Version 0.11 (June 20, 2022)

geopandas/geodataframe.py

@@ -148,7 +148,11 @@ class GeoDataFrame(GeoPandasBase, DataFrame):
             if crs is not None and data.crs != crs:
                 raise ValueError(crs_mismatch_error)
 
-        if geometry is None and "geometry" in self.columns:
+        if (
+            geometry is None
+            and self.columns.nlevels == 1
+            and "geometry" in self.columns
+        ):
             # Check for multiple columns with name "geometry". If there are,
             # self["geometry"] is a gdf and constructor gets recursively recalled
             # by pandas internals trying to access this

geopandas/tests/test_geodataframe.py

@@ -1220,6 +1220,25 @@ class TestConstructor:
         with pytest.raises(ValueError):
             GeoDataFrame(df3, geometry="geom")
 
+    @pytest.mark.parametrize("dtype", ["geometry", "object"])
+    def test_multiindex_with_geometry_label(self, dtype):
+        # DataFrame with MultiIndex where "geometry" label corresponds to
+        # multiple columns
+        df = pd.DataFrame([[Point(0, 0), Point(1, 1)], [Point(2, 2), Point(3, 3)]])
+        df = df.astype(dtype)
+        df.columns = pd.MultiIndex.from_product([["geometry"], [0, 1]])
+        # don't error in constructor
+        gdf = GeoDataFrame(df)
+        # Getting the .geometry column gives GeoDataFrame for both columns
+        # (but with first MultiIndex level removed)
+        # TODO should this give an error instead?
+        result = gdf.geometry
+        assert result.shape == gdf.shape
+        assert result.columns.tolist() == [0, 1]
+        assert_frame_equal(result, gdf["geometry"])
+        result = gdf[["geometry"]]
+        assert_frame_equal(result, gdf if dtype == "geometry" else pd.DataFrame(gdf))
+
 
 def test_geodataframe_crs():
     gdf = GeoDataFrame(columns=["geometry"])

geopandas/tests/test_op_output_types.py

@@ -289,6 +289,11 @@ def test_expanddim_in_unstack():
     else:  # pandas GH37369, unstack doesn't call finalize
         assert unstack._geometry_column_name == "geometry"
 
+    # https://github.com/geopandas/geopandas/issues/2486
+    s.name = "geometry"
+    unstack = s.unstack()
+    assert_object(unstack, GeoDataFrame, None, None)
+
 
 # indexing /  constructor_sliced tests
 

geopandas/tests/test_pandas_methods.py

@@ -657,6 +657,16 @@ def test_df_apply_returning_series(df):
     assert_series_equal(result, df["value1"].rename(None))
 
 
+def test_pivot(df):
+    # https://github.com/geopandas/geopandas/issues/2057
+    # pivot failing due to creating a MultiIndex
+    result = df.pivot(columns="value1")
+    expected = GeoDataFrame(pd.DataFrame(df).pivot(columns="value1"))
+    # TODO assert_geodataframe_equal crashes
+    assert isinstance(result, GeoDataFrame)
+    assert_frame_equal(result, expected)
+
+
 def test_preserve_attrs(df):
     # https://github.com/geopandas/geopandas/issues/1654
     df.attrs["name"] = "my_name"