Murisi/reverse conversion at source

.changelog/unreleased/bug-fixes/4287-consolidate-dust.md

@@ -0,0 +1,2 @@
+- Fix underestimation of MASP balances
+  ([\#4287](https://github.com/anoma/namada/pull/4287))

.changelog/unreleased/improvements/4288-reverse-conversion-at-source.md

@@ -0,0 +1,2 @@
+- Simplify exchanging balance amounts to older epochs
+  ([\#4288](https://github.com/anoma/namada/pull/4288))

crates/apps_lib/src/client/rpc.rs

@@ -524,7 +524,6 @@ async fn query_shielded_balance(
                 context.client(),
                 context.io(),
                 &viewing_key,
-                masp_epoch,
             )
             .await
             .unwrap()

crates/core/src/masp.rs

@@ -201,24 +201,35 @@ impl AssetData {
 
     /// Give this pre-asset type the given epoch if already has an epoch. Return
     /// the replaced value.
-    pub fn redate(&mut self, to: MaspEpoch) {
+    pub fn redate(self, to: MaspEpoch) -> Self {
         if self.epoch.is_some() {
-            self.epoch = Some(to);
+            Self {
+                epoch: Some(to),
+                ..self
+            }
+        } else {
+            self
         }
     }
 
     /// Update the MaspEpoch to the next one
-    pub fn redate_to_next_epoch(&mut self) {
-        if let Some(ep) = self.epoch.as_mut() {
-            if let Some(next) = ep.next() {
-                *ep = next;
+    pub fn redate_to_next_epoch(self) -> Self {
+        if let Some(next) = self.epoch.as_ref().and_then(MaspEpoch::next) {
+            Self {
+                epoch: Some(next),
+                ..self
             }
+        } else {
+            self
         }
     }
 
     /// Remove the epoch associated with this pre-asset type
-    pub fn undate(&mut self) {
-        self.epoch = None;
+    pub fn undate(self) -> Self {
+        Self {
+            epoch: None,
+            ..self
+        }
     }
 }
 
@@ -1128,23 +1139,23 @@ mod test {
 
     #[test]
     fn test_masp_asset_data_basics() {
-        let mut data = AssetData {
+        let data = AssetData {
             token: address::testing::nam(),
             denom: Denomination(6),
             position: MaspDigitPos::One,
             epoch: None,
         };
 
-        data.undate();
+        let data = data.undate();
         assert!(data.epoch.is_none());
 
         let epoch_0 = MaspEpoch::new(3);
-        data.redate(epoch_0);
+        let mut data = data.redate(epoch_0);
         assert!(data.epoch.is_none());
         data.epoch = Some(epoch_0);
 
         let epoch_1 = MaspEpoch::new(5);
-        data.redate(epoch_1);
+        let data = data.redate(epoch_1);
         assert_eq!(data.epoch, Some(epoch_1));
     }
 

crates/shielded_token/src/masp.rs

@@ -297,11 +297,6 @@ pub type MaspAmount = ValueSum<(Option<MaspEpoch>, Address), token::Change>;
 /// transaction
 pub type SpentNotesTracker = HashMap<ViewingKey, HashSet<usize>>;
 
-/// An extension of Option's cloned method for pair types
-fn cloned_pair<T: Clone, U: Clone>((a, b): (&T, &U)) -> (T, U) {
-    (a.clone(), b.clone())
-}
-
 /// Represents the amount used of different conversions
 pub type Conversions =
     BTreeMap<AssetType, (AllowedConversion, MerklePath<Node>, i128)>;