fix(typing): use cast for type hints

Author: lepture

src/joserfc/_keys.py

@@ -64,7 +64,7 @@ def import_key(cls, data: AnyKey, key_type: str | None = None, parameters: KeyPa
         """
         if isinstance(data, dict) and key_type is None:
             if "kty" in data:
-                key_type = data["kty"]  # type: ignore[assignment]
+                key_type = t.cast(str, data["kty"])
             else:
                 raise MissingKeyTypeError("Missing key type")
 

src/joserfc/_rfc8037/okp_key.py

@@ -128,7 +128,7 @@ class OKPKey(CurveKey[PrivateOKPKey, PublicOKPKey]):
 
     def exchange_derive_key(self, key: "OKPKey") -> bytes:
         # used in ECDH-ES Algorithms
-        pubkey: t.Union[X25519PublicKey, X448PublicKey] = key.get_op_key("deriveKey")  # type: ignore[assignment]
+        pubkey = t.cast(t.Union[X25519PublicKey, X448PublicKey], key.get_op_key("deriveKey"))
 
         # this if else logic is used for type hints
         if isinstance(self.private_key, X25519PrivateKey) and isinstance(pubkey, X25519PublicKey):

src/joserfc/jwe.py

@@ -1,5 +1,5 @@
 from __future__ import annotations
-from typing import overload
+from typing import cast, overload, Union
 from collections.abc import Collection
 from ._rfc7516.types import (
     GeneralJSONSerialization,
@@ -236,12 +236,12 @@ def decrypt_json(
 
     reject_unprotected_crit_header(data.get("unprotected"))
     if "recipients" in data:
-        general_obj = extract_general_json(data, registry)  # type: ignore[arg-type]
+        general_obj = extract_general_json(cast(GeneralJSONSerialization, data), registry)
         _attach_recipient_keys(general_obj.recipients, private_key, sender_key)
         perform_decrypt(general_obj, registry)
         return general_obj
     else:
-        flattened_obj = extract_flattened_json(data, registry)  # type: ignore[arg-type]
+        flattened_obj = extract_flattened_json(cast(FlattenedJSONSerialization, data), registry)
         _attach_recipient_keys(flattened_obj.recipients, private_key, sender_key)
         perform_decrypt(flattened_obj, registry)
         return flattened_obj
@@ -261,15 +261,18 @@ def _attach_recipient_keys(
 def _guess_sender_key(
     recipient: Recipient[Key], key: ECKey | OKPKey | KeySet, use_random: bool = False
 ) -> ECKey | OKPKey:
-    if isinstance(key, KeySet):
-        headers = recipient.headers()
-        skid = headers.get("skid")
-        if skid:
-            return key.get_by_kid(skid)  # type: ignore[return-value]
-        if use_random:
-            skey = key.pick_random_key(headers["alg"])
-            if skey is not None:
-                recipient.add_header("skid", skey.kid)
-                return skey  # type: ignore[return-value]
-        raise ValueError("Invalid key")
-    return key
+    if not isinstance(key, KeySet):
+        return key
+
+    headers = recipient.headers()
+    skid = headers.get("skid")
+    if skid:
+        skey = cast(Union[ECKey, OKPKey], key.get_by_kid(skid))
+        return skey
+
+    if use_random:
+        skey = cast(Union[ECKey, OKPKey], key.pick_random_key(headers["alg"]))
+        if skey is not None:
+            recipient.add_header("skid", skey.kid)
+            return skey
+    raise ValueError("Invalid key")