id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
27557	Overzealous GEOSGeometry sub-subclasses casts	Claude Paroz	nobody	"Reported by Pete Flugstad in https://groups.google.com/forum/#!topic/geodjango/-tao0uPNYY8

When writing a Point, Polygon, etc. subclass, the parent `GEOSGeometry._post_init` is force casting the instance to one of the hardcoded GEOSGeometry subclass, which breaks method overriding of the subclass.

Example:
{{{
from django.contrib.gis.geos import Polygon

class ExtendedPolygon(Polygon):
    def __init__(self, point_list, data=0 ): 
        super(ExtendedPolygon, self).__init__(point_list)
        self._data = data

    def __str__(self):
        return ""EXT_POLYGON - data: %d - %s"" % (self._data, self.wkt )
}}}

{{{
>>> from extpoly import ExtendedPolygon
>>> points = ((-75.1, 34.3), (-74.9, 34.3), (-74.9, 34.4), (-75.1, 34.4), (-75.1, 34.3))
>>> ex = ExtendedPolygon( points, altitude=123, speed=456, direction=789 )
>>> print(ex)
    POLYGON ((-75.09999999999999 34.3, -74.90000000000001 34.3, -74.90000000000001 34.4, -75.09999999999999 34.4, -75.09999999999999 34.3))
>>> type(ex)
    <class 'django.contrib.gis.geos.polygon.Polygon'>
}}}"	Bug	closed	GIS	dev	Normal	fixed			Ready for checkin	1	0	0	0	0	0