Raise the underlying cause when geospatial data cannot be read

test/io/test_geopandas.py

@@ -40,3 +40,18 @@ def test_load_xarray_with_from_file(gridpath):
     nc_filename = gridpath("scrip", "outCSne8", "outCSne8.nc")
     uxgrid = ux.Grid.from_file(nc_filename, backend="xarray")
     uxgrid.validate()
+
+
+def test_read_failure_raises(tmp_path):
+    """A read failure must surface its cause, not an UnboundLocalError.
+    Regression test for issue #1693."""
+    import pytest
+
+    from uxarray.errors import GridInvalidError
+    from uxarray.io._geopandas import _gpd_read
+
+    not_geospatial = tmp_path / "not_geospatial.shp"
+    not_geospatial.write_text("this is not a shapefile")
+
+    with pytest.raises(GridInvalidError, match="Could not read"):
+        _gpd_read(str(not_geospatial))

uxarray/io/_geopandas.py

@@ -3,6 +3,7 @@
 
 from uxarray.constants import INT_DTYPE, INT_FILL_VALUE, WGS84_CRS
 from uxarray.conventions import ugrid
+from uxarray.errors import GridInvalidError
 
 
 def _read_geodataframe(filepath, driver=None, **kwargs):
@@ -68,9 +69,12 @@ def _gpd_read(filepath, driver=None, **kwargs):
 
     try:
         gdf = gpd.read_file(filepath, driver=driver, **kwargs)
-        gdf = _set_crs(gdf)
     except Exception as e:
-        print(f"An error occurred while reading the geospatial data: {e}")
+        raise GridInvalidError(
+            f"Could not read geospatial data from {filepath!r}: {e}"
+        ) from e
+
+    gdf = _set_crs(gdf)
 
     max_polygon_nodes = gdf["geometry"].apply(_get_num_nodes).max()