🐛 Fix: 修复结构化并发子依赖取消缓存问题 (#3084)

nonebot/dependencies/__init__.py

@@ -21,7 +21,12 @@ from nonebot.log import logger
 from nonebot.typing import _DependentCallable
 from nonebot.exception import SkippedException
 from nonebot.compat import FieldInfo, ModelField, PydanticUndefined
-from nonebot.utils import run_sync, is_coroutine_callable, flatten_exception_group
+from nonebot.utils import (
+    run_sync,
+    run_coro_with_shield,
+    is_coroutine_callable,
+    flatten_exception_group,
+)
 
 from .utils import check_field_type, get_typed_signature
 
@@ -207,7 +212,10 @@ class Dependent(Generic[R]):
 
         async with anyio.create_task_group() as tg:
             for field in self.params:
-                tg.start_soon(_solve_field, field, params)
+                # shield the task to prevent cancellation
+                # when one of the tasks raises an exception
+                # this will improve the dependency cache reusability
+                tg.start_soon(run_coro_with_shield, _solve_field(field, params))
 
         return result
 

nonebot/internal/params.py

@@ -115,6 +115,9 @@ class DependencyCache:
         self._exception: Optional[BaseException] = None
         self._waiter = anyio.Event()
 
+    def done(self) -> bool:
+        return self._state == CacheState.FINISHED
+
     def result(self) -> Any:
         """获取子依赖结果"""
 
@@ -304,11 +307,18 @@ class DependParam(Param):
         dependency_cache[call] = cache = DependencyCache()
         try:
             result = await target
-            cache.set_result(result)
+        except Exception as e:
-            return result
-        except BaseException as e:
             cache.set_exception(e)
             raise
+        except BaseException as e:
+            cache.set_exception(e)
+            # remove cache when base exception occurs
+            # e.g. CancelledError
+            dependency_cache.pop(call, None)
+            raise
+        else:
+            cache.set_result(result)
+            return result
 
     @override
     async def _check(self, **kwargs: Any) -> None:

tests/plugins/param/param_depend.py

@@ -1,6 +1,7 @@
 from typing import Annotated
 from dataclasses import dataclass
 
+import anyio
 from pydantic import Field
 
 from nonebot import on_message
@@ -105,3 +106,26 @@ async def validate_field(x: int = Depends(lambda: "1", validate=Field(gt=0))):
 
 async def validate_field_fail(x: int = Depends(lambda: "0", validate=Field(gt=0))):
     return x
+
+
+async def _dep():
+    await anyio.sleep(1)
+    return 1
+
+
+def _dep_mismatch():
+    return 1
+
+
+async def cache_exception_func1(
+    dep: int = Depends(_dep),
+    mismatch: dict = Depends(_dep_mismatch),
+):
+    raise RuntimeError("Never reach here")
+
+
+async def cache_exception_func2(
+    dep: int = Depends(_dep),
+    match: int = Depends(_dep_mismatch),
+):
+    return dep

tests/test_param.py

@@ -51,6 +51,8 @@ async def test_depend(app: App):
         annotated_depend,
         sub_type_mismatch,
         validate_field_fail,
+        cache_exception_func1,
+        cache_exception_func2,
         annotated_class_depend,
         annotated_multi_depend,
         annotated_prior_depend,
@@ -130,6 +132,26 @@ async def test_depend(app: App):
     if isinstance(exc_info.value, BaseExceptionGroup):
         assert exc_info.group_contains(TypeMisMatch)
 
+    # test cache reuse when exception raised
+    dependency_cache = {}
+    with pytest.raises((TypeMisMatch, BaseExceptionGroup)) as exc_info:
+        async with app.test_dependent(
+            cache_exception_func1, allow_types=[DependParam]
+        ) as ctx:
+            ctx.pass_params(dependency_cache=dependency_cache)
+
+    if isinstance(exc_info.value, BaseExceptionGroup):
+        assert exc_info.group_contains(TypeMisMatch)
+
+    # dependency solve tasks should be shielded even if one of them raises an exception
+    assert len(dependency_cache) == 2
+
+    async with app.test_dependent(
+        cache_exception_func2, allow_types=[DependParam]
+    ) as ctx:
+        ctx.pass_params(dependency_cache=dependency_cache)
+        ctx.should_return(1)
+
 
 @pytest.mark.anyio
 async def test_bot(app: App):