Moved check_aggregate_support to BaseSpatialOperations

django/contrib/gis/db/backends/base/operations.py

@@ -102,6 +102,11 @@ class BaseSpatialOperations(object):
         """
         raise NotImplementedError('subclasses of BaseSpatialOperations must provide a geo_db_placeholder() method')
 
+    def check_aggregate_support(self, aggregate):
+        if aggregate.contains_aggregate == 'gis':
+            return aggregate.name in self.valid_aggregates
+        return super(BaseSpatialOperations, self).check_aggregate_support(aggregate)
+
     # Spatial SQL Construction
     def spatial_aggregate_sql(self, agg):
         raise NotImplementedError('Aggregate support not implemented for this spatial backend.')

django/contrib/gis/db/backends/mysql/operations.py

@@ -4,7 +4,7 @@ from django.contrib.gis.db.backends.utils import SpatialOperator
 from django.db.backends.mysql.operations import DatabaseOperations
 
 
-class MySQLOperations(DatabaseOperations, BaseSpatialOperations):
+class MySQLOperations(BaseSpatialOperations, DatabaseOperations):
 
     mysql = True
     name = 'mysql'

django/contrib/gis/db/backends/oracle/operations.py

@@ -52,7 +52,7 @@ class SDORelate(SpatialOperator):
         return super(SDORelate, self).as_sql(connection, lookup, template_params, sql_params)
 
 
-class OracleOperations(DatabaseOperations, BaseSpatialOperations):
+class OracleOperations(BaseSpatialOperations, DatabaseOperations):
 
     name = 'oracle'
     oracle = True

django/contrib/gis/db/backends/postgis/operations.py

@@ -43,7 +43,7 @@ class PostGISDistanceOperator(PostGISOperator):
         return super(PostGISDistanceOperator, self).as_sql(connection, lookup, template_params, sql_params)
 
 
-class PostGISOperations(DatabaseOperations, BaseSpatialOperations):
+class PostGISOperations(BaseSpatialOperations, DatabaseOperations):
     name = 'postgis'
     postgis = True
     geography = True
@@ -179,14 +179,6 @@ class PostGISOperations(DatabaseOperations, BaseSpatialOperations):
             version = vtup[1:]
         return version
 
-    def check_aggregate_support(self, aggregate):
-        """
-        Checks if the given aggregate name is supported (that is, if it's
-        in `self.valid_aggregates`).
-        """
-        agg_name = aggregate.__class__.__name__
-        return agg_name in self.valid_aggregates
-
     def convert_extent(self, box, srid):
         """
         Returns a 4-tuple extent for the `Extent` aggregate by converting

django/contrib/gis/db/backends/spatialite/operations.py

@@ -13,7 +13,7 @@ from django.utils import six
 from django.utils.functional import cached_property
 
 
-class SpatiaLiteOperations(DatabaseOperations, BaseSpatialOperations):
+class SpatiaLiteOperations(BaseSpatialOperations, DatabaseOperations):
     name = 'spatialite'
     spatialite = True
     version_regex = re.compile(r'^(?P<major>\d)\.(?P<minor1>\d)\.(?P<minor2>\d+)')
@@ -121,15 +121,6 @@ class SpatiaLiteOperations(DatabaseOperations, BaseSpatialOperations):
     def geojson(self):
         return 'AsGeoJSON' if self.spatial_version >= (3, 0, 0) else None
 
-    def check_aggregate_support(self, aggregate):
-        """
-        Checks if the given aggregate name is supported (that is, if it's
-        in `self.valid_aggregates`).
-        """
-        super(SpatiaLiteOperations, self).check_aggregate_support(aggregate)
-        agg_name = aggregate.__class__.__name__
-        return agg_name in self.valid_aggregates
-
     def convert_extent(self, box, srid):
         """
         Convert the polygon data received from Spatialite to min/max values.

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

@@ -7,6 +7,7 @@ __all__ = ['Collect', 'Extent', 'Extent3D', 'MakeLine', 'Union']
 class GeoAggregate(Aggregate):
     template = None
     function = None
+    contains_aggregate = 'gis'
     is_extent = False
 
     def as_sql(self, compiler, connection):

django/db/backends/base/features.py

@@ -224,6 +224,7 @@ class BaseDatabaseFeatures(object):
     def supports_stddev(self):
         """Confirm support for STDDEV and related stats functions."""
         class StdDevPop(object):
+            contains_aggregate = True
             sql_function = 'STDDEV_POP'
 
         try: