Additional type hints in sydent.db (#426)

We have to manually annotate return values of fetchone(), fetchmany() and fetchall(). (Unless we used something like sqlalchemy, hint hint)

Also remove a bytes -> unicode conversion. sqlite varchar is always `str` in python 3 so this is now redundant.

changelog.d/426.misc

@@ -0,0 +1 @@
+Type annotate the result of reading from the db in `sydent.db`.

sydent/db/accounts.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import TYPE_CHECKING, Optional, cast
+from typing import TYPE_CHECKING, Optional, Tuple, cast
 
 from sydent.users.accounts import Account
 
@@ -39,7 +39,7 @@ def getAccountByToken(self, token: str) -> Optional[Account]:
             (token,),
         )
 
-        row = res.fetchone()
+        row: Optional[Tuple[str, int, Optional[str]]] = res.fetchone()
         if row is None:
             return None
 

sydent/db/hashing_metadata.py

@@ -15,7 +15,9 @@
 # Actions on the hashing_metadata table which is defined in the migration process in
 # sqlitedb.py
 from sqlite3 import Cursor
-from typing import TYPE_CHECKING, Callable, Optional, Tuple
+from typing import TYPE_CHECKING, Callable, List, Optional, Tuple
+
+from typing_extensions import Literal
 
 if TYPE_CHECKING:
     from sydent.sydent import Sydent
@@ -87,7 +89,7 @@ def _rehash_threepids(
         cur: Cursor,
         hashing_function: Callable[[str], str],
         pepper: str,
-        table: str,
+        table: Literal["local_threepid_associations", "global_threepid_associations"],
     ) -> None:
         """Rehash 3PIDs of a given table using a given hashing_function and pepper
 
@@ -96,24 +98,17 @@ def _rehash_threepids(
         the made changes to the database.
 
         :param cur: Database cursor
-        :type cur:
-
         :param hashing_function: A function with single input and output strings
-        :type hashing_function func(str) -> str
-
         :param pepper: A pepper to append to the end of the 3PID (after a space) before hashing
-        :type pepper: str
-
         :param table: The database table to perform the rehashing on
-        :type table: str
         """
 
         # Get count of all 3PID records
         # Medium/address combos are marked as UNIQUE in the database
         sql = "SELECT COUNT(*) FROM %s" % table
         res = cur.execute(sql)
-        row_count = res.fetchone()
-        row_count = row_count[0]
+        row: Tuple[int] = res.fetchone()
+        row_count = row[0]
 
         # Iterate through each medium, address combo, hash it,
         # and store in the db
@@ -126,7 +121,7 @@ def _rehash_threepids(
                 count,
             )
             res = cur.execute(sql)
-            rows = res.fetchall()
+            rows: List[Tuple[str, str]] = res.fetchall()
 
             for medium, address in rows:
                 # Skip broken db entry

sydent/db/invite_tokens.py

@@ -12,12 +12,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import time
-from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Union, cast
+from typing import TYPE_CHECKING, List, Optional, Tuple, cast
+
+from typing_extensions import TypedDict
 
 if TYPE_CHECKING:
     from sydent.sydent import Sydent
 
 
+class PendingInviteTokens(TypedDict):
+    medium: str
+    address: str
+    room_id: str
+    sender: str
+    token: str
+
+
 class JoinTokenStore:
     def __init__(self, sydent: "Sydent") -> None:
         self.sydent = sydent
@@ -46,9 +56,7 @@ def storeToken(
         )
         self.sydent.db.commit()
 
-    def getTokens(
-        self, medium: str, address: str
-    ) -> List[Dict[str, Union[str, Dict[str, str]]]]:
+    def getTokens(self, medium: str, address: str) -> List[PendingInviteTokens]:
         """
         Retrieves the pending invites tokens for this 3PID that haven't been delivered
         yet.
@@ -69,25 +77,12 @@ def getTokens(
                 address,
             ),
         )
-        rows = res.fetchall()
+        rows: List[Tuple[str, str, str, str, str]] = res.fetchall()
 
-        ret = []
+        ret: List[PendingInviteTokens] = []
 
         for row in rows:
             medium, address, roomId, sender, token = row
-
-            # Ensure we're dealing with unicode.
-            if isinstance(medium, bytes):
-                medium = medium.decode("UTF-8")
-            if isinstance(address, bytes):
-                address = address.decode("UTF-8")
-            if isinstance(roomId, bytes):
-                roomId = roomId.decode("UTF-8")
-            if isinstance(sender, bytes):
-                sender = sender.decode("UTF-8")
-            if isinstance(token, bytes):
-                token = token.decode("UTF-8")
-
             ret.append(
                 {
                     "medium": medium,

sydent/db/threepid_associations.py

@@ -90,6 +90,16 @@ def getAssociationsAfterId(
         maxId = None
 
         assocs = {}
+        row: Tuple[
+            int,
+            str,
+            str,
+            Optional[str],
+            Optional[str],
+            Optional[int],
+            Optional[int],
+            Optional[int],
+        ]
         for row in res.fetchall():
             assoc = ThreepidAssociation(
                 row[1], row[2], row[3], row[4], row[5], row[6], row[7]
@@ -147,7 +157,7 @@ def removeAssociation(self, threepid: Dict[str, str], mxid: str) -> None:
             "WHERE medium = ? AND address = ? AND mxid = ?",
             (threepid["medium"], threepid["address"], mxid),
         )
-        row = cur.fetchone()
+        row: Tuple[int] = cur.fetchone()
         if row[0] > 0:
             ts = time_msec()
             cur.execute(
@@ -233,7 +243,7 @@ def getMxid(self, medium: str, normalised_address: str) -> Optional[str]:
             (medium, normalised_address, time_msec(), time_msec()),
         )
 
-        row: Tuple[str] = res.fetchone()
+        row: Tuple[Optional[str]] = res.fetchone()
 
         if not row:
             return None
@@ -281,6 +291,7 @@ def getMxids(
 
             results = []
             current = None
+            row: Tuple[str, str, int, str]
             for row in res.fetchall():
                 # only use the most recent entry for each
                 # threepid (they're sorted by ts)
@@ -429,6 +440,15 @@ def retrieveMxidsForHashes(self, addresses: List[str]) -> Dict[str, str]:
             # Place the results from the query into a dictionary
             # Results are sorted from oldest to newest, so if there are multiple mxid's for
             # the same lookup hash, only the newest mapping will be returned
+
+            # Type safety: lookup_hash is a nullable string in
+            # global_threepid_associations. But it must be equal to a lookup_hash
+            # in the temporary table thanks to the join condition.
+            # The temporary table gets hashes from the `addresses` argument,
+            # which is a list of (non-None) strings.
+            # So lookup_hash really is a str.
+            lookup_hash: str
+            mxid: str
             for lookup_hash, mxid in res.fetchall():
                 results[lookup_hash] = mxid
 

sydent/threepid/__init__.py

@@ -42,10 +42,12 @@ def __init__(
         medium: str,
         address: str,
         lookup_hash: Optional[str],
-        mxid: str,
-        ts: int,
-        not_before: int,
-        not_after: int,
+        # Note: the next four fields were made optional in schema version 2.
+        # See sydent.db.sqlitedb.SqliteDatabase._upgradeSchema
+        mxid: Optional[str],
+        ts: Optional[int],
+        not_before: Optional[int],
+        not_after: Optional[int],
     ):
         """
         :param medium: The medium of the 3pid (eg. email)

sydent/users/accounts.py

@@ -11,10 +11,13 @@
 # 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.
+from typing import Optional
 
 
 class Account:
-    def __init__(self, user_id: str, creation_ts: int, consent_version: str) -> None:
+    def __init__(
+        self, user_id: str, creation_ts: int, consent_version: Optional[str]
+    ) -> None:
         """
         :param user_id: The Matrix user ID for the account.
         :param creation_ts: The timestamp in milliseconds of the account's creation.