From 3411c5551aa4ec141eb214f2928db4b077b41dd3 Mon Sep 17 00:00:00 2001
From: Sergey Fedoseev <fedoseev.sergey@gmail.com>
Date: Mon, 9 Jul 2018 20:02:12 +0500
Subject: [PATCH] Refs #27472 -- Fixed crash during pickling of empty GEOS
 point.

---
 django/contrib/gis/geos/geometry.py     | 10 ++++++++--
 django/contrib/gis/geos/point.py        |  6 ++++++
 tests/gis_tests/geos_tests/test_geos.py |  3 ++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/django/contrib/gis/geos/geometry.py b/django/contrib/gis/geos/geometry.py
index 777e465883..4b3779938e 100644
--- a/django/contrib/gis/geos/geometry.py
+++ b/django/contrib/gis/geos/geometry.py
@@ -87,15 +87,21 @@ class GEOSGeometryBase(GEOSBase):
         return '<%s object at %s>' % (self.geom_type, hex(addressof(self.ptr)))
 
     # Pickling support
+    def _to_pickle_wkb(self):
+        return bytes(self.wkb)
+
+    def _from_pickle_wkb(self, wkb):
+        return wkb_r().read(memoryview(wkb))
+
     def __getstate__(self):
         # The pickled state is simply a tuple of the WKB (in string form)
         # and the SRID.
-        return bytes(self.wkb), self.srid
+        return self._to_pickle_wkb(), self.srid
 
     def __setstate__(self, state):
         # Instantiating from the tuple state that was pickled.
         wkb, srid = state
-        ptr = wkb_r().read(memoryview(wkb))
+        ptr = self._from_pickle_wkb(wkb)
         if not ptr:
             raise GEOSException('Invalid Geometry loaded from pickled state.')
         self.ptr = ptr
diff --git a/django/contrib/gis/geos/point.py b/django/contrib/gis/geos/point.py
index ccf5b9dbaf..24465f6324 100644
--- a/django/contrib/gis/geos/point.py
+++ b/django/contrib/gis/geos/point.py
@@ -40,6 +40,12 @@ class Point(GEOSGeometry):
         #  createPoint factory.
         super().__init__(point, srid=srid)
 
+    def _to_pickle_wkb(self):
+        return None if self.empty else super()._to_pickle_wkb()
+
+    def _from_pickle_wkb(self, wkb):
+        return self._create_empty() if wkb is None else super()._from_pickle_wkb(wkb)
+
     def _ogr_ptr(self):
         return gdal.geometries.Point._create_empty() if self.empty else super()._ogr_ptr()
 
diff --git a/tests/gis_tests/geos_tests/test_geos.py b/tests/gis_tests/geos_tests/test_geos.py
index 5f8d1c84b1..1924ccb356 100644
--- a/tests/gis_tests/geos_tests/test_geos.py
+++ b/tests/gis_tests/geos_tests/test_geos.py
@@ -1181,7 +1181,8 @@ class GEOSTest(SimpleTestCase, TestDataMixin):
         tgeoms.extend(get_geoms(self.geometries.multilinestrings, 4326))
         tgeoms.extend(get_geoms(self.geometries.polygons, 3084))
         tgeoms.extend(get_geoms(self.geometries.multipolygons, 3857))
-
+        tgeoms.append(Point(srid=4326))
+        tgeoms.append(Point())
         for geom in tgeoms:
             s1 = pickle.dumps(geom)
             g1 = pickle.loads(s1)