Question

I am trying to exercise a multi-party contract through Python ledger API. The DAML contract code as below,

**DAML Contract code which causes this issue:**
-- verification multi-party agreement block
controller Agent1 can
  ApproveScore : ContractId PendingContract 
    do create this with Agent1 = Agent2

行使合同的Ledger API代码，

执行该合同的Python Ledger API代码：

approve_exercise_command = ExerciseCommand(
   template_id = Identifier(
      package_id = self.package_id,name = PENDING_CONTRACT
    ),
    contract_id = event.created.contract_id,
    choice = APPROVE_CHOICE,
    choice_argument = Value(unit = Empty())
  )
  approve_score_command = Command(exercise = approve_exercise_command)

**Error details:**

    status = StatusCode.INVALID_ARGUMENT
        details = "DAMLe Error: Error(mismatching type: ApproveScore and value: ValueUnit)"
        debug_error_string = "{"created":"@1553510346.703290741","description":"Error received from peer","file":"src/core/lib/surface/call.cc","file_line":1039,"grpc_message":"DAMLe Error: Error(mismatching type: ApproveScore and value: ValueUnit)","grpc_status":3}"

Answer 1

DAML中用于选择的“无输入”表示为没有字段的记录类型；在您的示例中，该记录类型被命名为ApproveScore。

我不了解Python API的详细信息，但我想说的是，假设您的选择 did 有一些输入，围绕这些参数的脚手架会是什么样子喜欢？然后只需删除自变量，即可将支架（即空记录构造）保留在原处。

Answer 2

最后，我们在DA团队的帮助下找出了问题所在。问题是我使用Empty传递了Empty参数。使用最新版本的DA的SDK，我们将必须像下面那样传递空参数。

在旧版SDK中，要在选择中传递空参数，

choice_argument = Value(unit = Empty())

在新的SDK版本中，如下使用

 choice_argument = Value(
        record = Record(
         record_id = Identifier(
         package_id = self.package_id,
         name= "Main.ApproveScore"
        ),
       fields = [])
    )

谢谢Stephen Compall的加入。

DAMLe错误：错误（不匹配的类型：合同和价值：ValueUnit）

2 个答案: