Tried minting from transition in StateMachine an got error MintingPolicyNotFound

Question

I changed transition function in Lecture 7 and added constraint for minting Constraints.mustMintValue:

transition ts s r = case (stateValue s, stateData s, r) of
    (v, _, SetPrice p)   | p >= 0           -> Just ( Constraints.mustBeSignedBy (tsSeller ts) <>
                                                      Constraints.mustMintValue (assetClassValue (tsToken ts) 100)
                                                    , State p v
                                                    )

When I start emulator trace monad I am getting error in log:

Slot 00007: *** CONTRACT LOG: "SMCContractError (ConstraintResolutionError (MintingPolicyNotFound aa))"

I tried also with a different currencyPolicy than "aa", the real one that I got from Lecture 5 - Free.hs but I am getting the same result.

What is the proper way to do minting from State Machine?

Answer 1

I had this exact same issue with a StateMachine. I solved it by using runStepWith instead of runStep, which allows you to also supply the minting policy.

See the haddock documentation for details on how to use runStepWith