Tidy up and type-hint the database engine modules (#12734)

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

synapse/storage/engines/sqlite.py

@@ -12,21 +12,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import platform
+import sqlite3
 import struct
 import threading
-import typing
-from typing import Optional
+from typing import TYPE_CHECKING, Any, List, Mapping, Optional
 
 from synapse.storage.engines import BaseDatabaseEngine
-from synapse.storage.types import Connection
+from synapse.storage.types import Cursor
 
-if typing.TYPE_CHECKING:
-    import sqlite3  # noqa: F401
+if TYPE_CHECKING:
+    from synapse.storage.database import LoggingDatabaseConnection
 
 
-class Sqlite3Engine(BaseDatabaseEngine["sqlite3.Connection"]):
-    def __init__(self, database_module, database_config):
-        super().__init__(database_module, database_config)
+class Sqlite3Engine(BaseDatabaseEngine[sqlite3.Connection]):
+    def __init__(self, database_config: Mapping[str, Any]):
+        super().__init__(sqlite3, database_config)
 
         database = database_config.get("args", {}).get("database")
         self._is_in_memory = database in (
@@ -37,7 +37,7 @@ class Sqlite3Engine(BaseDatabaseEngine["sqlite3.Connection"]):
         if platform.python_implementation() == "PyPy":
             # pypy's sqlite3 module doesn't handle bytearrays, convert them
             # back to bytes.
-            database_module.register_adapter(bytearray, lambda array: bytes(array))
+            sqlite3.register_adapter(bytearray, lambda array: bytes(array))
 
         # The current max state_group, or None if we haven't looked
         # in the DB yet.
@@ -49,41 +49,43 @@ class Sqlite3Engine(BaseDatabaseEngine["sqlite3.Connection"]):
         return True
 
     @property
-    def can_native_upsert(self):
+    def can_native_upsert(self) -> bool:
         """
         Do we support native UPSERTs? This requires SQLite3 3.24+, plus some
         more work we haven't done yet to tell what was inserted vs updated.
         """
-        return self.module.sqlite_version_info >= (3, 24, 0)
+        return sqlite3.sqlite_version_info >= (3, 24, 0)
 
     @property
-    def supports_using_any_list(self):
+    def supports_using_any_list(self) -> bool:
         """Do we support using `a = ANY(?)` and passing a list"""
         return False
 
     @property
     def supports_returning(self) -> bool:
         """Do we support the `RETURNING` clause in insert/update/delete?"""
-        return self.module.sqlite_version_info >= (3, 35, 0)
+        return sqlite3.sqlite_version_info >= (3, 35, 0)
 
-    def check_database(self, db_conn, allow_outdated_version: bool = False):
+    def check_database(
+        self, db_conn: sqlite3.Connection, allow_outdated_version: bool = False
+    ) -> None:
         if not allow_outdated_version:
-            version = self.module.sqlite_version_info
+            version = sqlite3.sqlite_version_info
             # Synapse is untested against older SQLite versions, and we don't want
             # to let users upgrade to a version of Synapse with broken support for their
             # sqlite version, because it risks leaving them with a half-upgraded db.
             if version < (3, 22, 0):
                 raise RuntimeError("Synapse requires sqlite 3.22 or above.")
 
-    def check_new_database(self, txn):
+    def check_new_database(self, txn: Cursor) -> None:
         """Gets called when setting up a brand new database. This allows us to
         apply stricter checks on new databases versus existing database.
         """
 
-    def convert_param_style(self, sql):
+    def convert_param_style(self, sql: str) -> str:
         return sql
 
-    def on_new_connection(self, db_conn):
+    def on_new_connection(self, db_conn: "LoggingDatabaseConnection") -> None:
         # We need to import here to avoid an import loop.
         from synapse.storage.prepare_database import prepare_database
 
@@ -97,48 +99,46 @@ class Sqlite3Engine(BaseDatabaseEngine["sqlite3.Connection"]):
         db_conn.execute("PRAGMA foreign_keys = ON;")
         db_conn.commit()
 
-    def is_deadlock(self, error):
+    def is_deadlock(self, error: Exception) -> bool:
         return False
 
-    def is_connection_closed(self, conn):
+    def is_connection_closed(self, conn: sqlite3.Connection) -> bool:
         return False
 
-    def lock_table(self, txn, table):
+    def lock_table(self, txn: Cursor, table: str) -> None:
         return
 
     @property
-    def server_version(self):
-        """Gets a string giving the server version. For example: '3.22.0'
+    def server_version(self) -> str:
+        """Gets a string giving the server version. For example: '3.22.0'."""
+        return "%i.%i.%i" % sqlite3.sqlite_version_info
 
-        Returns:
-            string
-        """
-        return "%i.%i.%i" % self.module.sqlite_version_info
+    def in_transaction(self, conn: sqlite3.Connection) -> bool:
+        return conn.in_transaction
 
-    def in_transaction(self, conn: Connection) -> bool:
-        return conn.in_transaction  # type: ignore
-
-    def attempt_to_set_autocommit(self, conn: Connection, autocommit: bool):
+    def attempt_to_set_autocommit(
+        self, conn: sqlite3.Connection, autocommit: bool
+    ) -> None:
         # Twisted doesn't let us set attributes on the connections, so we can't
         # set the connection to autocommit mode.
         pass
 
     def attempt_to_set_isolation_level(
-        self, conn: Connection, isolation_level: Optional[int]
-    ):
-        # All transactions are SERIALIZABLE by default in sqllite
+        self, conn: sqlite3.Connection, isolation_level: Optional[int]
+    ) -> None:
+        # All transactions are SERIALIZABLE by default in sqlite
         pass
 
 
 # Following functions taken from: https://github.com/coleifer/peewee
 
 
-def _parse_match_info(buf):
+def _parse_match_info(buf: bytes) -> List[int]:
     bufsize = len(buf)
     return [struct.unpack("@I", buf[i : i + 4])[0] for i in range(0, bufsize, 4)]
 
 
-def _rank(raw_match_info):
+def _rank(raw_match_info: bytes) -> float:
     """Handle match_info called w/default args 'pcx' - based on the example rank
     function http://sqlite.org/fts3.html#appendix_a
     """