add contextvars and fix mutable default args

nonebot/matcher.py

@@ -6,14 +6,17 @@ import inspect
 from functools import wraps
 from datetime import datetime
 from collections import defaultdict
+from contextvars import Context, ContextVar, copy_context
 
 from nonebot.rule import Rule
 from nonebot.permission import Permission, USER
-from nonebot.typing import Bot, Event, Handler, ArgsParser
-from nonebot.typing import Type, List, Dict, Callable, Optional, NoReturn
+from nonebot.typing import Type, List, Dict, Union, Callable, Optional, NoReturn
+from nonebot.typing import Bot, Event, Handler, Message, ArgsParser, MessageSegment
 from nonebot.exception import PausedException, RejectedException, FinishedException
 
 matchers: Dict[int, List[Type["Matcher"]]] = defaultdict(list)
+current_bot: ContextVar = ContextVar("current_bot")
+current_event: ContextVar = ContextVar("current_event")
 
 
 class Matcher:
@@ -51,12 +54,12 @@ class Matcher:
             type_: str = "",
             rule: Rule = Rule(),
             permission: Permission = Permission(),
-            handlers: list = [],
+            handlers: Optional[list] = None,
             temp: bool = False,
             priority: int = 1,
             block: bool = False,
             *,
-            default_state: dict = {},
+            default_state: Optional[dict] = None,
             expire_time: Optional[datetime] = None) -> Type["Matcher"]:
         """创建新的 Matcher
 
@@ -69,12 +72,12 @@ class Matcher:
                 "type": type_,
                 "rule": rule,
                 "permission": permission,
-                "handlers": handlers,
+                "handlers": handlers or [],
                 "temp": temp,
                 "expire_time": expire_time,
                 "priority": priority,
                 "block": block,
-                "_default_state": default_state
+                "_default_state": default_state or {}
             })
 
         matchers[priority].append(NewMatcher)
@@ -117,12 +120,12 @@ class Matcher:
     def receive(cls) -> Callable[[Handler], Handler]:
         """接收一条新消息并处理"""
 
-        async def _handler(bot: Bot, event: Event, state: dict) -> NoReturn:
+        async def _receive(bot: Bot, event: Event, state: dict) -> NoReturn:
             raise PausedException
 
         if cls.handlers:
             # 已有前置handlers则接受一条新的消息，否则视为接收初始消息
-            cls.handlers.append(_handler)
+            cls.handlers.append(_receive)
 
         def _decorator(func: Handler) -> Handler:
             if not cls.handlers or cls.handlers[-1] is not func:
@@ -144,8 +147,7 @@ class Matcher:
             if key not in state:
                 state["_current_key"] = key
                 if prompt:
-                    await bot.send_private_msg(user_id=event.user_id,
-                                               message=prompt)
+                    await bot.send(event=event, message=prompt)
                 raise PausedException
 
         async def _key_parser(bot: Bot, event: Event, state: dict):
@@ -176,19 +178,42 @@ class Matcher:
         return _decorator
 
     @classmethod
-    def finish(cls) -> NoReturn:
+    async def finish(
+        cls,
+        prompt: Optional[Union[str, Message,
+                               MessageSegment]] = None) -> NoReturn:
+        bot: Bot = current_bot.get()
+        event: Event = current_event.get()
+        if prompt:
+            await bot.send(event=event, message=prompt)
         raise FinishedException
 
     @classmethod
-    def pause(cls) -> NoReturn:
+    async def pause(
+        cls,
+        prompt: Optional[Union[str, Message,
+                               MessageSegment]] = None) -> NoReturn:
+        bot: Bot = current_bot.get()
+        event: Event = current_event.get()
+        if prompt:
+            await bot.send(event=event, message=prompt)
         raise PausedException
 
     @classmethod
-    def reject(cls) -> NoReturn:
+    async def reject(
+        cls,
+        prompt: Optional[Union[str, Message,
+                               MessageSegment]] = None) -> NoReturn:
+        bot: Bot = current_bot.get()
+        event: Event = current_event.get()
+        if prompt:
+            await bot.send(event=event, message=prompt)
         raise RejectedException
 
     # 运行handlers
     async def run(self, bot: Bot, event: Event, state: dict):
+        b_t = current_bot.set(bot)
+        e_t = current_event.set(event)
         try:
             # Refresh preprocess state
             self.state.update(state)
@@ -214,7 +239,6 @@ class Matcher:
                 block=True,
                 default_state=self.state,
                 expire_time=datetime.now() + bot.config.session_expire_timeout)
-            return
         except PausedException:
             Matcher.new(
                 self.type,
@@ -226,6 +250,8 @@ class Matcher:
                 block=True,
                 default_state=self.state,
                 expire_time=datetime.now() + bot.config.session_expire_timeout)
-            return
         except FinishedException:
-            return
+            pass
+        finally:
+            current_bot.reset(b_t)
+            current_event.reset(e_t)