bpo-43258: Don't allocate sqlite3 aggregate context for empty queries (GH-24569)
diff --git a/Lib/sqlite3/test/userfunctions.py b/Lib/sqlite3/test/userfunctions.py
index 2285abd..749ea04 100644
--- a/Lib/sqlite3/test/userfunctions.py
+++ b/Lib/sqlite3/test/userfunctions.py
@@ -429,6 +429,11 @@ def test_aggr_check_aggr_sum(self):
val = cur.fetchone()[0]
self.assertEqual(val, 60)
+ def test_aggr_no_match(self):
+ cur = self.con.execute("select mysum(i) from (select 1 as i) where i == 0")
+ val = cur.fetchone()[0]
+ self.assertIsNone(val)
+
class AuthorizerTests(unittest.TestCase):
@staticmethod
def authorizer_cb(action, arg1, arg2, dbname, source):
diff --git a/Misc/NEWS.d/next/Library/2021-02-18-23-30-52.bpo-43258.LeU-q8.rst b/Misc/NEWS.d/next/Library/2021-02-18-23-30-52.bpo-43258.LeU-q8.rst
new file mode 100644
index 0000000..0529214
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-02-18-23-30-52.bpo-43258.LeU-q8.rst
@@ -0,0 +1,2 @@
+Prevent needless allocation of :mod:`sqlite3` aggregate function context
+when no rows match an aggregate query. Patch by Erlend E. Aasland.
diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index 63fcb00..39b55fc 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -708,8 +708,12 @@ void _pysqlite_final_callback(sqlite3_context* context)
threadstate = PyGILState_Ensure();
- aggregate_instance = (PyObject**)sqlite3_aggregate_context(context, sizeof(PyObject*));
- if (!*aggregate_instance) {
+ aggregate_instance = (PyObject**)sqlite3_aggregate_context(context, 0);
+ if (aggregate_instance == NULL) {
+ /* No rows matched the query; the step handler was never called. */
+ goto error;
+ }
+ else if (!*aggregate_instance) {
/* this branch is executed if there was an exception in the aggregate's
* __init__ */