from fastapi import Depends, FastAPI, HTTPException
from typing_extensions import Annotated

app = FastAPI()


class InternalError(Exception):
    pass


def get_username():
    try:
        yield "Rick"
    except InternalError:
        print("We don't swallow the internal error here, we raise again 😎")
        raise


@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):

    "tf.IfRegion"(%0) ( {
      %2 = "tf.A"() : () -> (tensor<f32>)
      "tf.Yield"() : () -> ()
      }, {
      "tf.Yield"() : () -> ()
     }) { is_stateless = true } : (tensor<i1>) -> ()
    "tf.IfRegion"(%0) ( {
      %2 = "tf.B"() : () -> (tensor<f32>)
      "tf.Yield"() : () -> ()
      }, {
      "tf.Yield"() : () -> ()
      }) { is_stateless = true } : (tensor<i1>) -> ()
    ```

    }
    val result = plans[nextPlanIndex++]
    events += "take plan ${result.id}"

    if (result.yieldBeforePlanReturns) {
      taskFaker.yield()
    }

    val planningThrowable = result.planningThrowable
    if (planningThrowable != null) throw planningThrowable

    return result
  }

                val declarationName = declaration.nameAsName ?: continue
                if (!nameFilter(declarationName)) continue
                with(analysisSession) {
                    yield(declaration.getSymbol() as S)
                }
            }
        }
    }

    override fun getConstructors(): Sequence<KaConstructorSymbol> = withValidityAssertion {
        emptySequence()
    }

    SmallVector<Type, 16> func_operand_types;
    func_operand_types.reserve(operands.size());
    for (Value operand : operands)
      func_operand_types.push_back(operand.getType());

    // Function results are the yield operands
    SmallVector<Type, 16> func_result_types;
    for (Value operand : island_op.GetYield().getOperands())
      func_result_types.push_back(operand.getType());
    FunctionType func_type =

    // match the "func.return" within the function.
    //
    // So this would transform
    // func.func @f(...) -> ... {
    //     yield %x : foo
    // }
    // ...
    // func.call @f(...) -> bar
    //
    // to
    //
    // func.func @f(...) -> ... {
    //     yield %x : foo
    // }
    // ...
    // func.call f(...) -> foo
    auto symbol_uses = f.getSymbolUses(f->getParentOp());

    我们将`SessionLocal()`请求的创建和处理放在一个`try`块中。

    然后我们在finally块中关闭它。

    通过这种方式，我们确保数据库会话在请求后始终关闭。即使在处理请求时出现异常。

    但是您不能从退出代码中引发另一个异常（在yield之后）。可以查阅 [Dependencies with yield and HTTPException](https://fastapi.tiangolo.com/zh/tutorial/dependencies/dependencies-with-yield/#dependencies-with-yield-and-httpexception)

*然后，当在路径操作函数*中使用依赖项时，我们使用`Session`，直接从 SQLAlchemy 导入的类型声明它。

*这将为我们在路径操作函数*中提供更好的编辑器支持，因为编辑器将知道`db`参数的类型`Session`：

//
// For greater control over the traversal of each subtree, use [Inspect].
func Preorder(root Node) iter.Seq[Node] {
	return func(yield func(Node) bool) {
		ok := true
		Inspect(root, func(n Node) bool {
			if n != nil {
				// yield must not be called once ok is false.
				ok = ok && yield(n)
			}
			return ok
		})
	}

)

// Readdir reads the contents of the directory associated with file and
// returns a slice of up to n [FileInfo] values, as would be returned
// by [Lstat], in directory order. Subsequent calls on the same file will yield
// further FileInfos.
//
// If n > 0, Readdir returns at most n FileInfo structures. In this case, if
// Readdir returns an empty slice, it will return a non-nil error

  %graph = tf_executor.graph {
    %island, %ctrl = tf_executor.island {
      %pred = "tf.SomeOp"(%arg2) : (tensor<f32>) -> tensor<i32>
      tf_executor.yield %pred : tensor<i32>
    }
    tf_executor.fetch %island : tensor<i32>
  }
  func.return %graph : tensor<i32>
}

// CHECK-LABEL:   func @simple_independent_chains