🎨 change typing for formatter

nonebot/adapters/_formatter.py

@@ -1,59 +1,49 @@
 import functools
 import operator
 from string import Formatter
-from typing import (Any, Generic, List, Mapping, Protocol, Sequence, Set, Tuple,
-                    Type, TypeVar, Union, TYPE_CHECKING)
+from typing import (Any, Set, List, Type, Tuple, Union, TypeVar, Mapping,
+                    Generic, Sequence, TYPE_CHECKING)
 
 if TYPE_CHECKING:
-    from nonebot.adapters import Message
+    from . import Message, MessageSegment
+
+TM = TypeVar("TM", bound="Message")
+TMS = TypeVar("TMS", bound="MessageSegment")
+TAddable = Union[str, TM, TMS]
 
 
-class AddAble(Protocol):
+class MessageFormatter(Formatter, Generic[TM, TMS]):
 
-    def __add__(self, __s: Any) -> "AddAble":
-        ...
-
-    def __str__(self) -> str:
-        ...
-
-
-AddAble_T = TypeVar("AddAble_T", bound=AddAble)
-MessageResult_T = TypeVar("MessageResult_T", bound="Message", covariant=True)
-
-
-class MessageFormatter(Formatter, Generic[MessageResult_T]):
-
-    def __init__(self, factory: Type[MessageResult_T], template: str) -> None:
-        super().__init__()
+    def __init__(self, factory: Type[TM], template: str) -> None:
         self.template = template
         self.factory = factory
 
-    def format(self, *args: AddAble, **kwargs: AddAble) -> MessageResult_T:
-        msg: AddAble = super().format(self.template, *args, **kwargs)
-        return msg if isinstance(msg, self.factory) else self.factory(
-            msg)  # type: ignore
+    def format(self, *args: TAddable[TM, TMS], **kwargs: TAddable[TM,
+                                                                  TMS]) -> TM:
+        msg = self.vformat(self.template, args, kwargs)
+        return msg if isinstance(msg, self.factory) else self.factory(msg)
 
-    def vformat(self, format_string: str, args: Sequence[AddAble],
-                kwargs: Mapping[str, AddAble]):
-        result, arg_index, used_args = self._vformat(format_string, args,
-                                                     kwargs, set(), 2)
+    def vformat(self, format_string: str, args: Sequence[TAddable[TM, TMS]],
+                kwargs: Mapping[str, TAddable[TM, TMS]]) -> TM:
+        used_args = set()
+        result, _ = self._vformat(format_string, args, kwargs, used_args, 2)
         self.check_unused_args(list(used_args), args, kwargs)
         return result
 
     def _vformat(
         self,
         format_string: str,
-        args: Sequence[Any],
-        kwargs: Mapping[str, Any],
+        args: Sequence[TAddable[TM, TMS]],
+        kwargs: Mapping[str, TAddable[TM, TMS]],
         used_args: Set[Union[int, str]],
         recursion_depth: int,
         auto_arg_index: int = 0,
-    ) -> Tuple[AddAble, int, Set[Union[int, str]]]:
+    ) -> Tuple[TM, int]:
 
         if recursion_depth < 0:
             raise ValueError("Max string recursion exceeded")
 
-        results: List[AddAble] = []
+        results: List[TAddable[TM, TMS]] = []
 
         for (literal_text, field_name, format_spec,
              conversion) in self.parse(format_string):
@@ -95,24 +85,23 @@ class MessageFormatter(Formatter, Generic[MessageResult_T]):
                 obj = self.convert_field(obj, conversion) if conversion else obj
 
                 # expand the format spec, if needed
-                format_control, auto_arg_index, formatted_args = self._vformat(
+                format_control, auto_arg_index = self._vformat(
                     format_spec,
                     args,
                     kwargs,
-                    used_args.copy(),
+                    used_args,
                     recursion_depth - 1,
                     auto_arg_index,
                 )
-                used_args |= formatted_args
 
                 # format the object and append to the result
                 formatted_text = self.format_field(obj, str(format_control))
                 results.append(formatted_text)
 
-        return functools.reduce(operator.add, results or
-                                [""]), auto_arg_index, used_args
+        return self.factory(functools.reduce(operator.add, results or
+                                             [""])), auto_arg_index
 
-    def format_field(self, value: AddAble_T,
-                     format_spec: str) -> Union[AddAble_T, str]:
+    def format_field(self, value: TAddable[TM, TMS],
+                     format_spec: str) -> TAddable[TM, TMS]:
         return super().format_field(value,
                                     format_spec) if format_spec else value