Raise ValueError when get_resource() is called with optional=True and…

… wait_error=True

src/asphalt/core/_context.py

@@ -586,14 +586,19 @@ async def get_resource(
         :param wait: if ``True``, wait for the resource to become available if it's not
             already available in the context chain
         :param optional: if ``True``, return ``None`` if the resource was not available
+        :raises ValueError: if both ``optional=True`` and ``wait=True`` were specified,
+            as it doesn't make sense
         :return: the requested resource, or ``None`` if none was available and
             ``optional`` was ``False``
 
         """
         self._ensure_state(ContextState.open, ContextState.closing)
-        key = (type, name)
+
+        if wait and optional:
+            raise ValueError("combining wait=True and optional=True doesn't make sense")
 
         # First check if there's already a matching resource in this context
+        key = (type, name)
         if (resource := self._resources.get(key)) is not None:
             return cast(T_Resource, resource.value_or_factory)
 

tests/test_context.py

@@ -351,6 +351,10 @@ async def test_get_resource_not_found(self, context: Context) -> None:
         assert exc.value.type == int
         assert exc.value.name == "foo"
 
+    async def test_get_resource_optional_wait(self, context: Context) -> None:
+        with pytest.raises(ValueError, match="doesn't make sense"):
+            await context.get_resource(int, optional=True, wait=True)
+
     async def test_start_service_task_cancel_on_exit(self) -> None:
         started = False
         finished = False