FetchByKey.daml

{-
-*- mode: haskell;-*-
-}
module FetchByKey where

template TKey
  with
    p : Party
  where
    signatory p
    key p : Party
    maintainer key

template Helper
  with
    p : Party
  where
    signatory p
    choice FetchKey : (ContractId TKey, TKey)
      with
        k : Party
      controller p
      do fetchByKey @TKey k

template T
  with
    p1 : Party
    p2 : Party
  where
    signatory p1
    observer p2
    nonconsuming choice C : (ContractId TKey, TKey)
      with
        k : Party
      controller p2
      do createAndExercise (Helper p1) (FetchKey k)

test = do
  p1 <- getParty "p1"
  p2 <- getParty "p2"
  submit p1 (create (TKey p1))
  submit p2 (create (TKey p2))
  cid <- submit p1 (create (T p1 p2))
  -- submitter p2 is not a stakeholder
  submitMustFail p2 (exercise cid (C p1))
  -- submitter p2 is a stakeholder but we only have authorization from p1
  submitMustFail p2 (exercise cid (C p2))
  pure ()