From 694008ad941d3066315620f77a2dbe05f96ed2b6 Mon Sep 17 00:00:00 2001
From: Pablo Lamela <pablo.lamela@iohk.io>
Date: Thu, 31 Oct 2024 14:15:22 +0100
Subject: [PATCH] Add function to access anchor data from `GovAction` and fix
 typo

---
 cardano-api/internal/Cardano/Api/Certificate.hs  |  2 +-
 .../Api/Governance/Actions/ProposalProcedure.hs  | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/cardano-api/internal/Cardano/Api/Certificate.hs b/cardano-api/internal/Cardano/Api/Certificate.hs
index 94ef89fab7..dc1c7ee494 100644
--- a/cardano-api/internal/Cardano/Api/Certificate.hs
+++ b/cardano-api/internal/Cardano/Api/Certificate.hs
@@ -743,7 +743,7 @@ instance Error AnchorDataFromCertificateError where
   prettyError (InvalidPoolMetadataHashError url hash) =
     "Invalid pool metadata hash for URL " <> fromString (show url) <> ": " <> fromString (show hash)
 
--- | Get anchor data hash from a certificate. A return value of `Nothing`
+-- | Get anchor data url and hash from a certificate. A return value of `Nothing`
 -- means that the certificate does not contain anchor data.
 getAnchorDataFromCertificate
   :: Certificate era
diff --git a/cardano-api/internal/Cardano/Api/Governance/Actions/ProposalProcedure.hs b/cardano-api/internal/Cardano/Api/Governance/Actions/ProposalProcedure.hs
index 6f4b202ae0..fb4ff3b934 100644
--- a/cardano-api/internal/Cardano/Api/Governance/Actions/ProposalProcedure.hs
+++ b/cardano-api/internal/Cardano/Api/Governance/Actions/ProposalProcedure.hs
@@ -230,3 +230,19 @@ createAnchor url anchorData =
     { anchorUrl = url
     , anchorDataHash = hashAnchorData $ Ledger.AnchorData anchorData
     }
+
+-- | Get anchor data url and hash from a governance action. A return value of `Nothing`
+-- means that the governance action does not contain anchor data.
+getAnchorDataFromGovernanceAction
+  :: EraCrypto (ShelleyLedgerEra era) ~ StandardCrypto
+  => Gov.GovAction (ShelleyLedgerEra era)
+  -> Maybe (Ledger.Anchor StandardCrypto)
+getAnchorDataFromGovernanceAction govAction =
+  case govAction of
+    Gov.ParameterChange{} -> Nothing
+    Gov.HardForkInitiation _ _ -> Nothing
+    Gov.TreasuryWithdrawals _ _ -> Nothing
+    Gov.NoConfidence _ -> Nothing
+    Gov.UpdateCommittee{} -> Nothing
+    Gov.NewConstitution _ constitution -> Just $ Ledger.constitutionAnchor constitution
+    Gov.InfoAction -> Nothing