Fixed #27603 -- Fixed AsKML when queryset is evaluated more than once.

Author: sir-sigurd

django/contrib/gis/db/models/functions.py

@@ -195,8 +195,9 @@ def as_oracle(self, compiler, connection, **extra_context):
 class AsKML(AsGML):
     def as_sqlite(self, compiler, connection):
         # No version parameter
-        self.source_expressions.pop(0)
-        return super().as_sql(compiler, connection)
+        clone = self.copy()
+        clone.set_source_expressions(self.get_source_expressions()[1:])
+        return clone.as_sql(compiler, connection)
 
 
 class AsSVG(GeoFunc):

tests/gis_tests/geoapp/test_functions.py

@@ -118,8 +118,11 @@ def test_askml(self):
             City.objects.annotate(kml=functions.AsKML('name'))
 
         # Ensuring the KML is as expected.
-        ptown = City.objects.annotate(kml=functions.AsKML('point', precision=9)).get(name='Pueblo')
+        qs = City.objects.annotate(kml=functions.AsKML('point', precision=9))
+        ptown = qs.get(name='Pueblo')
         self.assertEqual('<Point><coordinates>-104.609252,38.255001</coordinates></Point>', ptown.kml)
+        # Same result if the queryset is evaluated again.
+        self.assertEqual(qs.get(name='Pueblo').kml, ptown.kml)
 
     @skipUnlessDBFeature("has_AsSVG_function")
     def test_assvg(self):