[3.12] pythongh-129346: Handle allocation errors for SQLite aggregate context (pythonGH-129347) (python#129373)

(cherry picked from commit 379ab85)

Co-authored-by: Erlend E. Aasland <[email protected]>

Author: miss-islington

Misc/NEWS.d/next/Library/2025-01-27-14-05-19.gh-issue-129346.gZRd3g.rst

@@ -0,0 +1,2 @@
+In :mod:`sqlite3`, handle out-of-memory when creating user-defined SQL
+functions.

Modules/_sqlite/connection.c

@@ -927,6 +927,11 @@ step_callback(sqlite3_context *context, int argc, sqlite3_value **params)
     assert(ctx != NULL);
 
     aggregate_instance = (PyObject**)sqlite3_aggregate_context(context, sizeof(PyObject*));
+    if (aggregate_instance == NULL) {
+        (void)PyErr_NoMemory();
+        set_sqlite_error(context, "unable to allocate SQLite aggregate context");
+        goto error;
+    }
     if (*aggregate_instance == NULL) {
         *aggregate_instance = PyObject_CallNoArgs(ctx->callable);
         if (!*aggregate_instance) {