remove caching weirdness and improve change detection

sdk/src/client/api/block_builder/transaction_builder/mod.rs

@@ -210,7 +210,7 @@ pub(crate) struct MinManaAllotment {
     required_allotment: Option<u64>,
 }
 
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub(crate) struct Remainders {
     address: Option<Address>,
     data: Vec<RemainderData>,
@@ -545,11 +545,6 @@ impl TransactionBuilder {
             .expect("expiration unlockable outputs already filtered out");
         self.selected_inputs.insert(required_address, input);
 
-        // Remove the cached allotment value because it's no longer valid
-        if let Some(MinManaAllotment { required_allotment, .. }) = self.min_mana_allotment.as_mut() {
-            *required_allotment = None;
-        }
-
         Ok(added_output)
     }
 

sdk/src/client/api/block_builder/transaction_builder/remainder.rs

@@ -20,12 +20,14 @@ use crate::{
 };
 
 impl TransactionBuilder {
-    /// Updates the remainders, overwriting old values.
-    pub(crate) fn update_remainders(&mut self) -> Result<(), TransactionBuilderError> {
-        self.remainders = Remainders {
-            address: self.remainders.address.take(),
+    /// Updates the remainders, overwriting old values. Returns whether any changes were made.
+    pub(crate) fn update_remainders(&mut self) -> Result<bool, TransactionBuilderError> {
+        // Swap the remainders so we can keep the old ones to compare to later.
+        let mut old_remainders = Remainders {
+            address: self.remainders.address.clone(),
             ..Default::default()
         };
+        core::mem::swap(&mut self.remainders, &mut old_remainders);
         let (input_amount, output_amount, inputs_sdr, outputs_sdr) = self.amount_sums();
 
         for (address, amount) in inputs_sdr {
@@ -120,12 +122,11 @@ impl TransactionBuilder {
 
         if amount_diff == 0 && mana_diff == 0 && native_tokens_diff.is_empty() {
             log::debug!("No remainder required");
-            return Ok(());
+        } else {
+            self.create_remainder_outputs(amount_diff, mana_diff, native_tokens_diff, remainder_address, chain)?;
         }
 
-        self.create_remainder_outputs(amount_diff, mana_diff, native_tokens_diff, remainder_address, chain)?;
-
-        Ok(())
+        Ok(self.remainders != old_remainders)
     }
 
     /// Gets the remainder address from configuration or finds one from the inputs.

sdk/src/client/api/block_builder/transaction_builder/requirement/mana.rs

@@ -66,7 +66,7 @@ impl TransactionBuilder {
         // Remainders can only be calculated when the input mana is >= the output mana
         let (input_mana, output_mana) = self.mana_sums(false)?;
         if input_mana >= output_mana {
-            self.update_remainders()?;
+            should_recalculate |= self.update_remainders()?;
         }
 
         should_recalculate |= self.get_inputs_for_mana_balance()?;
@@ -89,7 +89,7 @@ impl TransactionBuilder {
             return Ok(None);
         };
 
-        if required_allotment.is_none() && !self.selected_inputs.is_empty() && self.all_outputs().next().is_some() {
+        if !self.selected_inputs.is_empty() && self.all_outputs().next().is_some() {
             let inputs = self
                 .selected_inputs
                 .sorted_iter()
@@ -301,7 +301,10 @@ impl TransactionBuilder {
 
     pub(crate) fn mana_sums(&mut self, include_remainders: bool) -> Result<(u64, u64), TransactionBuilderError> {
         let allotments_sum = if let Some(MinManaAllotment { issuer_id, .. }) = self.min_mana_allotment {
-            let required_allotment = self.required_allotment()?.unwrap_or_default();
+            let mut required_allotment = self.min_mana_allotment.and_then(|a| a.required_allotment);
+            if required_allotment.is_none() {
+                required_allotment = self.required_allotment()?;
+            }
             self.mana_allotments
                 .iter()
                 .filter_map(|(id, value)| (id != &issuer_id).then_some(value))
@@ -311,7 +314,7 @@ impl TransactionBuilder {
                     .get(&issuer_id)
                     .copied()
                     .unwrap_or_default()
-                    .max(required_allotment)
+                    .max(required_allotment.unwrap_or_default())
         } else {
             self.mana_allotments.values().sum::<u64>()
         };