Fix failing gouraud shading mask creation in pccolormesh

lib/cartopy/mpl/geoaxes.py

@@ -1893,7 +1893,7 @@ def _wrap_quadmesh(self, collection, **kwargs):
                           "It is recommended to remove the wrap manually "
                           "before calling pcolormesh.")
             # With gouraud shading, we actually want an (Ny, Nx) shaped mask
-            gmask = np.zeros(data_shape, dtype=bool)
+            gmask = np.zeros((data_shape[0], data_shape[1]), dtype=bool)
             # If any of the cells were wrapped, apply it to all 4 corners
             gmask[:-1, :-1] |= mask
             gmask[1:, :-1] |= mask

lib/cartopy/tests/mpl/test_mpl_integration.py

@@ -654,6 +654,17 @@ def test_pcolormesh_single_column_wrap():
     return fig
 
 
+def test_pcolormesh_wrap_gouraud_shading_failing_mask_creation():
+    x_range = np.linspace(-180, 180, 50)
+    y_range = np.linspace(90, -90, 50)
+    x, y = np.meshgrid(x_range, y_range)
+    data = ((np.sin(np.deg2rad(x))) / 10. + np.exp(np.cos(np.deg2rad(y))))
+
+    fig = plt.figure(figsize=(10, 6))
+    ax = fig.add_subplot(1, 1, 1, projection=ccrs.Mercator())
+    ax.pcolormesh(x, y, data, transform=ccrs.PlateCarree(), shading='gouraud')
+
+
 def test_pcolormesh_diagonal_wrap():
     # Check that a cell with the top edge on one side of the domain
     # and the bottom edge on the other gets wrapped properly