style(python): modernize type annotations in protobuf.py

python/src/trezorlib/protobuf.py

@@ -22,23 +22,25 @@ For de-serializing (loading) protobuf types, object with `Reader` interface is r
 For serializing (dumping) protobuf types, object with `Writer` interface is required.
 """
 
+from __future__ import annotations
+
 import logging
 import warnings
 from dataclasses import dataclass
 from enum import IntEnum
 from io import BytesIO
 from itertools import zip_longest
-from typing import Any, Dict, List, Optional, Tuple, Type, TypeVar, Union
+import typing as t
 
-from typing_extensions import Protocol, TypeGuard
+import typing_extensions as tx
 
-T = TypeVar("T", bound=type)
-MT = TypeVar("MT", bound="MessageType")
+T = t.TypeVar("T", bound=type)
+MT = t.TypeVar("MT", bound="MessageType")
 
 MAX_FIELD_SIZE = 1024 * 1024  # 1 MB
 
 
-class Reader(Protocol):
+class Reader(tx.Protocol):
     def readinto(self, __buf: bytearray) -> int:
         """
         Reads exactly `len(buffer)` bytes into `buffer`. Returns number of bytes read,
@@ -47,7 +49,7 @@ class Reader(Protocol):
         ...
 
 
-class Writer(Protocol):
+class Writer(tx.Protocol):
     def write(self, __buf: bytes) -> int:
         """
         Writes all bytes from `buffer`, or raises `EOFError`
@@ -60,7 +62,7 @@ _UVARINT_BUFFER = bytearray(1)
 LOG = logging.getLogger(__name__)
 
 
-def safe_issubclass(value: Any, cls: Union[T, Tuple[T, ...]]) -> TypeGuard[T]:
+def safe_issubclass(value: t.Any, cls: T | tuple[T, ...]) -> tx.TypeGuard[T]:
     return isinstance(value, type) and issubclass(value, cls)
 
 
@@ -189,15 +191,15 @@ class _MessageTypeMeta(type):
 
 
 class MessageType(metaclass=_MessageTypeMeta):
-    MESSAGE_WIRE_TYPE: Optional[int] = None
+    MESSAGE_WIRE_TYPE: t.ClassVar[int | None] = None
 
-    FIELDS: Dict[int, Field] = {}
+    FIELDS: t.ClassVar[dict[int, Field]] = {}
 
     @classmethod
-    def get_field(cls, name: str) -> Optional[Field]:
+    def get_field(cls, name: str) -> Field | None:
         return next((f for f in cls.FIELDS.values() if f.name == name), None)
 
-    def __init__(self, *args: Any, **kwargs: Any) -> None:
+    def __init__(self, *args: t.Any, **kwargs: t.Any) -> None:
         if args:
             warnings.warn(
                 "Positional arguments for MessageType are deprecated",
@@ -220,7 +222,7 @@ class MessageType(metaclass=_MessageTypeMeta):
                 # set in args but not in kwargs
                 setattr(self, field.name, val)
             else:
-                default: Any
+                default: t.Any
                 # not set at all, pick a default
                 if field.repeated:
                     default = []
@@ -235,7 +237,7 @@ class MessageType(metaclass=_MessageTypeMeta):
                     default = field.default
                 setattr(self, field.name, default)
 
-    def __eq__(self, rhs: Any) -> bool:
+    def __eq__(self, rhs: t.Any) -> bool:
         return self.__class__ is rhs.__class__ and self.__dict__ == rhs.__dict__
 
     def __repr__(self) -> str:
@@ -276,9 +278,7 @@ class CountingWriter:
         return nwritten
 
 
-def get_field_type_object(
-    field: Field,
-) -> Optional[Union[Type[MessageType], Type[IntEnum]]]:
+def get_field_type_object(field: Field) -> type[MessageType] | type[IntEnum] | None:
     from . import messages
 
     field_type_object = getattr(messages, field.type, None)
@@ -287,7 +287,7 @@ def get_field_type_object(
     return field_type_object
 
 
-def decode_packed_array_field(field: Field, reader: Reader) -> List[Any]:
+def decode_packed_array_field(field: Field, reader: Reader) -> list[t.Any]:
     assert field.repeated, "Not decoding packed array into non-repeated field"
     length = load_uvarint(reader)
     packed_reader = LimitedReader(reader, length)
@@ -300,7 +300,7 @@ def decode_packed_array_field(field: Field, reader: Reader) -> List[Any]:
     return values
 
 
-def decode_varint_field(field: Field, reader: Reader) -> Union[int, bool, IntEnum]:
+def decode_varint_field(field: Field, reader: Reader) -> int | bool | IntEnum:
     assert field.wire_type == WIRE_TYPE_INT, f"Field {field.name} is not varint-encoded"
     value = load_uvarint(reader)
 
@@ -336,7 +336,7 @@ def decode_varint_field(field: Field, reader: Reader) -> Union[int, bool, IntEnu
 
 def decode_length_delimited_field(
     field: Field, reader: Reader
-) -> Union[bytes, str, MessageType]:
+) -> bytes | str | MessageType:
     value = load_uvarint(reader)
     if value > MAX_FIELD_SIZE:
         raise ValueError(f"Field {field.name} contents too large ({value} bytes)")
@@ -358,8 +358,8 @@ def decode_length_delimited_field(
     raise TypeError  # field type is unknown
 
 
-def load_message(reader: Reader, msg_type: Type[MT]) -> MT:
-    msg_dict: Dict[str, Any] = {}
+def load_message(reader: Reader, msg_type: type[MT]) -> MT:
+    msg_dict: dict[str, t.Any] = {}
     # pre-seed the dict
     for field in msg_type.FIELDS.values():
         if field.repeated:
@@ -500,8 +500,8 @@ def format_message(
     pb: "MessageType",
     indent: int = 0,
     sep: str = " " * 4,
-    truncate_after: Optional[int] = 256,
-    truncate_to: Optional[int] = 64,
+    truncate_after: int | None = 256,
+    truncate_to: int | None = 64,
 ) -> str:
     def mostly_printable(bytes: bytes) -> bool:
         if not bytes:
@@ -509,7 +509,7 @@ def format_message(
         printable = sum(1 for byte in bytes if 0x20 <= byte <= 0x7E)
         return printable / len(bytes) > 0.8
 
-    def pformat(name: str, value: Any, indent: int) -> str:
+    def pformat(name: str, value: t.Any, indent: int) -> str:
         level = sep * indent
         leadin = sep * (indent + 1)
 
@@ -568,7 +568,7 @@ def format_message(
     )
 
 
-def value_to_proto(field: Field, value: Any) -> Any:
+def value_to_proto(field: Field, value: t.Any) -> t.Any:
     field_type_object = get_field_type_object(field)
     if safe_issubclass(field_type_object, MessageType):
         raise TypeError("value_to_proto only converts simple values")
@@ -601,7 +601,7 @@ def value_to_proto(field: Field, value: Any) -> Any:
             raise TypeError(f"can't convert {type(value)} value to bytes")
 
 
-def dict_to_proto(message_type: Type[MT], d: Dict[str, Any]) -> MT:
+def dict_to_proto(message_type: type[MT], d: dict[str, t.Any]) -> MT:
     params = {}
     for field in message_type.FIELDS.values():
         value = d.get(field.name)
@@ -624,8 +624,8 @@ def dict_to_proto(message_type: Type[MT], d: Dict[str, Any]) -> MT:
     return message_type(**params)
 
 
-def to_dict(msg: "MessageType", hexlify_bytes: bool = True) -> Dict[str, Any]:
-    def convert_value(value: Any) -> Any:
+def to_dict(msg: "MessageType", hexlify_bytes: bool = True) -> dict[str, t.Any]:
+    def convert_value(value: t.Any) -> t.Any:
         if hexlify_bytes and isinstance(value, bytes):
             return value.hex()
         elif isinstance(value, MessageType):