Only import sqlite3 when type checking

Fixes: #7127
Signed-off-by: David Vo <david@vovo.id.au>

2 files changed, 6 insertions, 2 deletions

diff --git a/changelog.d/7155.bugfix b/changelog.d/7155.bugfix
new file mode 100644

index 0000000000..0bf51e7aba
--- /dev/null
+++ b/changelog.d/7155.bugfix
@@ -0,0 +1 @@
+Avoid importing `sqlite3` when using the postgres backend. Contributed by David Vo.
diff --git a/synapse/storage/engines/sqlite.py b/synapse/storage/engines/sqlite.py

index 2bfeefd54e..3bc2e8b986 100644
--- a/synapse/storage/engines/sqlite.py
+++ b/synapse/storage/engines/sqlite.py
@@ -12,14 +12,17 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import sqlite3
 import struct
 import threading
+import typing
 
 from synapse.storage.engines import BaseDatabaseEngine
 
+if typing.TYPE_CHECKING:
+    import sqlite3  # noqa: F401
 
-class Sqlite3Engine(BaseDatabaseEngine[sqlite3.Connection]):
+
+class Sqlite3Engine(BaseDatabaseEngine["sqlite3.Connection"]):
     def __init__(self, database_module, database_config):
         super().__init__(database_module, database_config)