From a4f9ef4fe8048264c5d9e193e2ff79f735626c65 Mon Sep 17 00:00:00 2001
From: Sergey Fedoseev <fedoseev.sergey@gmail.com>
Date: Tue, 7 Nov 2017 19:49:29 +0500
Subject: [PATCH] Refs #28518 -- Improved performance of assigning values to
 GeometryFields.

---
 django/contrib/gis/db/models/fields.py | 2 +-
 django/contrib/gis/db/models/proxy.py  | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/django/contrib/gis/db/models/fields.py b/django/contrib/gis/db/models/fields.py
index e43d7ccc2ed..f0329b2ec12 100644
--- a/django/contrib/gis/db/models/fields.py
+++ b/django/contrib/gis/db/models/fields.py
@@ -247,7 +247,7 @@ class GeometryField(BaseSpatialField):
         super().contribute_to_class(cls, name, **kwargs)
 
         # Setup for lazy-instantiated Geometry object.
-        setattr(cls, self.attname, SpatialProxy(GEOSGeometry, self))
+        setattr(cls, self.attname, SpatialProxy(self.geom_class or GEOSGeometry, self, load_func=GEOSGeometry))
 
     def formfield(self, **kwargs):
         defaults = {'form_class': self.form_class,
diff --git a/django/contrib/gis/db/models/proxy.py b/django/contrib/gis/db/models/proxy.py
index 3c306cceb0c..06d64873d99 100644
--- a/django/contrib/gis/db/models/proxy.py
+++ b/django/contrib/gis/db/models/proxy.py
@@ -9,13 +9,14 @@ from django.db.models.query_utils import DeferredAttribute
 
 
 class SpatialProxy(DeferredAttribute):
-    def __init__(self, klass, field):
+    def __init__(self, klass, field, load_func=None):
         """
         Initialize on the given Geometry or Raster class (not an instance)
         and the corresponding field.
         """
         self._field = field
         self._klass = klass
+        self._load_func = load_func or klass
         super().__init__(field.attname, klass)
 
     def __get__(self, instance, cls=None):
@@ -42,7 +43,7 @@ class SpatialProxy(DeferredAttribute):
         else:
             # Otherwise, a geometry or raster object is built using the field's
             # contents, and the model's corresponding attribute is set.
-            geo_obj = self._klass(geo_value)
+            geo_obj = self._load_func(geo_value)
             setattr(instance, self._field.attname, geo_obj)
         return geo_obj
 
@@ -61,7 +62,7 @@ class SpatialProxy(DeferredAttribute):
             # For raster fields, assure input is None or a string, dict, or
             # raster instance.
             pass
-        elif isinstance(value, self._klass) and (str(value.geom_type).upper() == gtype or gtype == 'GEOMETRY'):
+        elif isinstance(value, self._klass):
             # The geometry type must match that of the field -- unless the
             # general GeometryField is used.
             if value.srid is None: