GIS layermapping utility fails to import linestrings

[elpaso66]

It seems like there is an error in type comparison around line 288, objects gtype and ltype are tested for equality while probably their string values should be tested instead.

File: trunk/django/contrib/gis/utils/layermapping.py

The patch below should fix this issue and give a more complete error message.

@@ -288,9 +288,10 @@
                     raise LayerMapError('Invalid mapping for GeometryField "%s".' % field_name)

                 # Making sure that the OGR Layer's Geometry is compatible.
+
                 ltype = self.layer.geom_type
-                if not (gtype == ltype or self.make_multi(ltype, model_field)):
-                    raise LayerMapError('Invalid mapping geometry; model has %s, feature has %s.' % (fld_name, gtype))
+                if not (str(gtype) == str(ltype) or self.make_multi(ltype, model_field)):
+                    raise LayerMapError('Invalid mapping geometry; model has %s, feature has %s instead of %s.' % (fld_name, gtype,  ltype))

[jbronn]

Because gtype is really an OGRGeomType instance, equality testing with strings works (e.g., OGRGeomType('POINT') == 'Point'). Regardless, for other reasons it was changed to a string comparison in r11742 when 3D support was added; I also clarified that exception to differentiate between the model field type and what was found on the layer, similar to what you put in the summary here.

While I agree there was a problem with the error message, the LayerMapping utility has always been able to import LineString geometries, it's done in the test suite in multiple places.