Merge pull request #2778 from jku/type-fixes

Author: jku

tuf/api/dsse.py

@@ -81,7 +81,7 @@ def from_bytes(cls, data: bytes) -> SimpleEnvelope[T]:
         except Exception as e:
             raise DeserializationError from e
 
-        return envelope
+        return cast(SimpleEnvelope[T], envelope)
 
     def to_bytes(self) -> bytes:
         """Return envelope as JSON bytes.

tuf/api/serialization/json.py

@@ -98,7 +98,10 @@ def serialize(self, signed_obj: Signed) -> bytes:
         """
         try:
             signed_dict = signed_obj.to_dict()
-            canonical_bytes = encode_canonical(signed_dict).encode("utf-8")
+            canon_str = encode_canonical(signed_dict)
+            # encode_canonical cannot return None if output_function is not set
+            assert canon_str is not None  # noqa: S101
+            canonical_bytes = canon_str.encode("utf-8")
 
         except Exception as e:
             raise SerializationError from e