bpo-41815: SQLite: segfault if backup called on closed database (GH-22322)
# [bpo-41815](): SQLite: fix segfault if backup called on closed database
Attempting to backup a closed database will trigger segfault:
```python
import sqlite3
target = sqlite3.connect(':memory:')
source = sqlite3.connect(':memory:')
source.close()
source.backup(target)
```diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index f765ba1..81fc133 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -1514,6 +1514,10 @@
sleep_ms = (int)ms;
}
+ if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
+ return NULL;
+ }
+
if (!pysqlite_check_connection((pysqlite_Connection *)target)) {
return NULL;
}