wip2

zebra-chain/src/orchard_zsa/asset_state.rs

@@ -204,6 +204,11 @@ impl AssetStateChange {
         self.is_finalized |= change.is_finalized;
         self.supply_change.add(change.supply_change)
     }
+
+    /// Returns true if the AssetStateChange is for an asset burn.
+    pub fn is_burn(&self) -> bool {
+        matches!(self.supply_change, SupplyChange::Burn(_))
+    }
 }
 
 /// An `issued_asset` map
@@ -240,7 +245,7 @@ impl IntoIterator for IssuedAssets {
 }
 
 /// A map of changes to apply to the issued assets map.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub struct IssuedAssetsChange(HashMap<AssetBase, AssetStateChange>);
 
 impl IssuedAssetsChange {

zebra-consensus/src/block.rs

@@ -315,18 +315,17 @@ where
             let new_outputs = Arc::into_inner(known_utxos)
                 .expect("all verification tasks using known_utxos are complete");
 
-            let (burns, issuance) = IssuedAssetsChange::from_transactions(&block.transactions);
+            let issued_assets_change = IssuedAssetsChange::from_transactions(&block.transactions)
+                .ok_or("invalid asset issuance or burns")?;
+
             let prepared_block = zs::SemanticallyVerifiedBlock {
                 block,
                 hash,
                 height,
                 new_outputs,
                 transaction_hashes,
                 deferred_balance: Some(expected_deferred_amount),
-                issued_assets_changes: IssuedAssetsOrChanges::BurnAndIssuanceChanges {
-                    burns,
-                    issuance,
-                },
+                issued_assets_change: Some(issued_assets_change),
             };
 
             // Return early for proposal requests when getblocktemplate-rpcs feature is enabled

zebra-state/src/request.rs

@@ -166,7 +166,7 @@ pub struct SemanticallyVerifiedBlock {
     pub deferred_balance: Option<Amount<NonNegative>>,
     /// A map of burns to be applied to the issued assets map.
     // TODO: Reference ZIP.
-    pub issued_assets_changes: IssuedAssetsOrChanges,
+    pub issued_assets_change: Option<IssuedAssetsChange>,
 }
 
 /// A block ready to be committed directly to the finalized state with
@@ -317,26 +317,6 @@ pub enum IssuedAssetsOrChanges {
 
     /// A map of changes to apply to the issued assets map.
     Change(IssuedAssetsChange),
-
-    /// A map of changes from burns and issuance to apply to the issued assets map.
-    BurnAndIssuanceChanges {
-        /// A map of changes from burns to apply to the issued assets map.
-        burns: IssuedAssetsChange,
-        /// A map of changes from issuance to apply to the issued assets map.
-        issuance: IssuedAssetsChange,
-    },
-}
-
-impl IssuedAssetsOrChanges {
-    /// Combines fields in the `BurnAndIssuanceChanges` variant then returns a `Change` variant, or
-    /// returns self unmodified.
-    pub fn combine(self) -> Self {
-        let Self::BurnAndIssuanceChanges { burns, issuance } = self else {
-            return self;
-        };
-
-        Self::Change(burns + issuance)
-    }
 }
 
 impl From<IssuedAssetsChange> for IssuedAssetsOrChanges {
@@ -369,7 +349,7 @@ impl FinalizedBlock {
             transaction_hashes: block.transaction_hashes,
             treestate,
             deferred_balance: block.deferred_balance,
-            issued_assets: block.issued_assets_changes,
+            issued_assets: block.issued_assets_change,
         }
     }
 }

zebra-state/src/service/check/issuance.rs

@@ -4,7 +4,7 @@ use std::{collections::HashMap, sync::Arc};
 
 use zebra_chain::orchard_zsa::IssuedAssets;
 
-use crate::{IssuedAssetsOrChanges, SemanticallyVerifiedBlock, ValidateContextError, ZebraDb};
+use crate::{SemanticallyVerifiedBlock, ValidateContextError, ZebraDb};
 
 use super::Chain;
 
@@ -13,45 +13,34 @@ pub fn valid_burns_and_issuance(
     parent_chain: &Arc<Chain>,
     semantically_verified: &SemanticallyVerifiedBlock,
 ) -> Result<IssuedAssets, ValidateContextError> {
-    let IssuedAssetsOrChanges::BurnAndIssuanceChanges { burns, issuance } =
-        semantically_verified.issued_assets_changes.clone()
-    else {
-        panic!("unexpected variant in semantically verified block")
+    let Some(issued_assets_change) = semantically_verified.issued_assets_change.clone() else {
+        return Ok(IssuedAssets::default());
     };
 
     let mut issued_assets = HashMap::new();
 
-    for (asset_base, burn_change) in burns.clone() {
-        // TODO: Move this to a read fn.
-        let updated_asset_state = parent_chain
-            .issued_asset(&asset_base)
-            .or_else(|| finalized_state.issued_asset(&asset_base))
-            .ok_or(ValidateContextError::InvalidBurn)?
-            .apply_change(burn_change)
-            .ok_or(ValidateContextError::InvalidBurn)?;
-
-        issued_assets
-            .insert(asset_base, updated_asset_state)
-            .expect("transactions must have only one burn item per asset base");
-    }
-
-    for (asset_base, issuance_change) in issuance.clone() {
-        // TODO: Move this to a read fn.
-        let Some(asset_state) = issued_assets
+    for (asset_base, change) in issued_assets_change {
+        let asset_state = issued_assets
             .get(&asset_base)
             .copied()
             .or_else(|| parent_chain.issued_asset(&asset_base))
-            .or_else(|| finalized_state.issued_asset(&asset_base))
-        else {
-            continue;
-        };
+            .or_else(|| finalized_state.issued_asset(&asset_base));
 
-        let _ = issued_assets.insert(
-            asset_base,
+        let updated_asset_state = if change.is_burn() {
             asset_state
-                .apply_change(issuance_change)
-                .ok_or(ValidateContextError::InvalidIssuance)?,
-        );
+                .ok_or(ValidateContextError::InvalidBurn)?
+                .apply_change(change)
+                .ok_or(ValidateContextError::InvalidBurn)?
+        } else {
+            asset_state
+                .unwrap_or_default()
+                .apply_change(change)
+                .ok_or(ValidateContextError::InvalidIssuance)?
+        };
+
+        issued_assets
+            .insert(asset_base, updated_asset_state)
+            .expect("transactions must have only one burn item per asset base");
     }
 
     Ok(issued_assets.into())