parameterize PST policy only with assetclass of GST

...to resolve the cyclic reference between SST and PST

agora-test/Spec/Sample/Shared.hs

@@ -119,7 +119,7 @@ proposal =
     }
 
 proposalPolicySymbol :: CurrencySymbol
-proposalPolicySymbol = mintingPolicySymbol $ mkMintingPolicy (proposalPolicy proposal)
+proposalPolicySymbol = mintingPolicySymbol $ mkMintingPolicy (proposalPolicy proposal.governorSTAssetClass)
 
 -- | A sample 'PubKeyHash'.
 signer :: PubKeyHash

agora/Agora/Governor/Scripts.hs

@@ -23,6 +23,7 @@ module Agora.Governor.Scripts (
   stakeValidatorHashFromGovernor,
   proposalFromGovernor,
   proposalValidatorHashFromGovernor,
+  proposalSTSymbolFromGovernor,
 ) where
 
 --------------------------------------------------------------------------------
@@ -698,18 +699,17 @@ atSymbolFromGovernor gov = mintingPolicySymbol policy
     at = AuthorityToken $ governorSTAssetClassFromGovernor gov
     policy = mkMintingPolicy $ authorityTokenPolicy at
 
+proposalSTSymbolFromGovernor :: Governor -> CurrencySymbol
+proposalSTSymbolFromGovernor gov = symbol
+  where
+    gstAC = governorSTAssetClassFromGovernor gov
+    policy = mkMintingPolicy $ proposalPolicy gstAC
+    symbol = mintingPolicySymbol policy
+
 proposalSTAssetClassFromGovernor :: Governor -> AssetClass
 proposalSTAssetClassFromGovernor gov = AssetClass (symbol, "")
   where
-    gstAC = governorSTAssetClassFromGovernor gov
-    -- JUSTIFICATION: the PST policy doesn't care about the following two fields at all.
-    -- FIXME: refactor PST policy, parameterize it only with GST assetclass or something.
-    sstAC = AssetClass ("", "")
-    mc = -1
-    params = Proposal gstAC sstAC mc
-
-    policy = mkMintingPolicy $ proposalPolicy params
-    symbol = mintingPolicySymbol policy
+    symbol = proposalSTSymbolFromGovernor gov
 
 stakeSTSymbolFromGovernor :: Governor -> CurrencySymbol
 stakeSTSymbolFromGovernor gov = mintingPolicySymbol policy

agora/Agora/Proposal/Scripts.hs

@@ -58,8 +58,11 @@ import Plutus.V1.Ledger.Value (AssetClass (AssetClass))
 
    - This policy cannot be burned.
 -}
-proposalPolicy :: Proposal -> ClosedTerm PMintingPolicy
-proposalPolicy proposal =
+proposalPolicy ::
+  -- | The assetclass of GST, see 'Agora.Governor.Scripts.governorPolicy'.
+  AssetClass ->
+  ClosedTerm PMintingPolicy
+proposalPolicy (AssetClass (govCs, govTn)) =
   plam $ \_redeemer ctx' -> P.do
     PScriptContext ctx' <- pmatch ctx'
     ctx <- pletFields @'["txInfo", "purpose"] ctx'
@@ -69,7 +72,6 @@ proposalPolicy proposal =
 
     let inputs = txInfo.inputs
         mintedValue = pfromData txInfo.mint
-        AssetClass (govCs, govTn) = proposal.governorSTAssetClass
 
     PMinting ownSymbol' <- pmatch $ pfromData ctx.purpose
     let mintedProposalST =
@@ -145,7 +147,7 @@ proposalValidator proposal =
     ownAddress <- plet $ txOutF.address
 
     let stCurrencySymbol =
-          pconstant $ getMintingPolicySymbol (proposalPolicy proposal)
+          pconstant $ getMintingPolicySymbol (proposalPolicy proposal.governorSTAssetClass)
     valueSpent <- plet $ pvalueSpent # txInfoF.inputs
     spentST <- plet $ psymbolValueOf # stCurrencySymbol #$ valueSpent
     let AssetClass (stakeSym, stakeTn) = proposal.stakeSTAssetClass