Oracle backend returns empty string instead of None for empty geometries

[Sergey Fedoseev]

from django.contrib.gis.geos.geometry import GEOSGeometry
from django.contrib.gis.db.models.functions import Intersection
from test_app.models import City

City.objects.annotate(inter=Intersection('point', GEOSGeometry('POINT (0 0)', srid=4326))).values('inter')

<QuerySet [{'inter': u''}]>

from django.db import connection

c = connection.cursor()
c.execute('SELECT "TEST_APP_CITY"."ID", SDO_UTIL.TO_WKTGEOMETRY(SDO_GEOM.SDO_INTERSECTION("TEST_APP_CITY"."POINT", SDO_GEOMETRY(\'POINT(0 0)\', 4326), 0.05)) AS "INTER" FROM "TEST_APP_CITY"')
.fetchall()

[('1', None)]

[Sergey Fedoseev]

​PR

[Tim Graham <timograham@…>]

In ea466506:

Fixed #26785 -- Made Oracle return None rather than empty string for empty geometries.

[Tim Graham <timograham@…>]

In be1022d0:

[1.10.x] Fixed #26785 -- Made Oracle return None rather than empty string for empty geometries.

Backport of ea4665066b651e0e2730f2e2d85fcef9d7ac7966 from master