Fix upcoming sparse change - squash warnings on init errors (#396)

CHANGES.rst

@@ -5,6 +5,7 @@ What's new
 ------------------
 * Fix ESMpy memory issues by explictly freeing the Grid memory upon garbage collection of ``Regridder`` objects. By `Pascal Bourgault <https://github.com/aulemahal>`_.
 * Address deprecation for xarray 2024.10 in the parallel weight generation. By `Pascal Bourgault <https://github.com/aulemahal>`_.
+* Address an upcoming change in sparse 0.16 where COO fill values will distinguish between 0.0 and -0.0. This issue would affect spatial averaging over polygons with holes. By `Pascal Bourgault <https://github.com/aulemahal>`_.
 
 0.8.7 (2024-07-16)
 ------------------

xesmf/frontend.py

@@ -1112,8 +1112,9 @@ def _format_xroutput(self, out, new_dims=None):
     def __del__(self):
         # Memory leak issue when regridding over a large number of datasets with xESMF
         # https://github.com/JiaweiZhuang/xESMF/issues/53
-        self.grid_in.destroy()
-        self.grid_out.destroy()
+        if hasattr(self, 'grid_in'):  # If the init has failed, grid_in isn't there
+            self.grid_in.destroy()
+            self.grid_out.destroy()
 
 
 class SpatialAverager(BaseRegridder):
@@ -1324,7 +1325,10 @@ def _compute_weights(self):
             w_int, area_int = self._compute_weights_and_area(mesh_int)
 
             # Append weights from holes as negative weights
-            w = xr.concat((w, -w_int), 'out_dim')
+            # In sparse >= 0.16, a fill_value of -0.0 is different from 0.0 and the concat would fail
+            inv_w_int = -w_int
+            inv_w_int.data.fill_value = 0.0
+            w = xr.concat((w, inv_w_int), 'out_dim')
 
             # Append areas
             area = np.concatenate([area, area_int])
@@ -1382,5 +1386,6 @@ def _format_xroutput(self, out, new_dims=None):
     def __del__(self):
         # Memory leak issue when regridding over a large number of datasets with xESMF
         # https://github.com/JiaweiZhuang/xESMF/issues/53
-        self.grid_in.destroy()
-        self.grid_out.destroy()
+        if hasattr(self, 'grid_in'):  # If the init has failed, grid_in isn't there
+            self.grid_in.destroy()
+            self.grid_out.destroy()