add type annotations to freeze functions

nominatim/db/connection.py

@@ -77,7 +77,7 @@ class _Cursor(psycopg2.extras.DictCursor):
         self.execute(pysql.SQL(sql).format(pysql.Identifier(name))) # type: ignore
 
 
-class _Connection(psycopg2.extensions.connection):
+class Connection(psycopg2.extensions.connection):
     """ A connection that provides the specialised cursor by default and
         adds convenience functions for administrating the database.
     """
@@ -174,19 +174,22 @@ class _Connection(psycopg2.extensions.connection):
 
         return (int(version_parts[0]), int(version_parts[1]))
 
-class _ConnectionContext(ContextManager[_Connection]):
-    connection: _Connection
+class ConnectionContext(ContextManager[Connection]):
+    """ Context manager of the connection that also provides direct access
+        to the underlying connection.
+    """
+    connection: Connection
 
-def connect(dsn: str) -> _ConnectionContext:
+def connect(dsn: str) -> ConnectionContext:
     """ Open a connection to the database using the specialised connection
         factory. The returned object may be used in conjunction with 'with'.
         When used outside a context manager, use the `connection` attribute
         to get the connection.
     """
     try:
-        conn = psycopg2.connect(dsn, connection_factory=_Connection)
-        ctxmgr = cast(_ConnectionContext, contextlib.closing(conn))
-        ctxmgr.connection = cast(_Connection, conn)
+        conn = psycopg2.connect(dsn, connection_factory=Connection)
+        ctxmgr = cast(ConnectionContext, contextlib.closing(conn))
+        ctxmgr.connection = cast(Connection, conn)
         return ctxmgr
     except psycopg2.OperationalError as err:
         raise UsageError(f"Cannot connect to database: {err}") from err

nominatim/tools/freeze.py

@@ -7,10 +7,13 @@
 """
 Functions for removing unnecessary data from the database.
 """
+from typing import Optional
 from pathlib import Path
 
 from psycopg2 import sql as pysql
 
+from nominatim.db.connection import Connection
+
 UPDATE_TABLES = [
     'address_levels',
     'gb_postcode',
@@ -25,7 +28,7 @@ UPDATE_TABLES = [
     'wikipedia_%'
 ]
 
-def drop_update_tables(conn):
+def drop_update_tables(conn: Connection) -> None:
     """ Drop all tables only necessary for updating the database from
         OSM replication data.
     """
@@ -42,7 +45,7 @@ def drop_update_tables(conn):
     conn.commit()
 
 
-def drop_flatnode_file(fpath):
+def drop_flatnode_file(fpath: Optional[Path]) -> None:
     """ Remove the flatnode file if it exists.
     """
     if fpath and fpath.exists():