bank::get_rent_collector_from_parent (#23016)

runtime/src/bank.rs

@@ -1509,6 +1509,10 @@ impl Bank {
         )
     }
 
+    fn get_rent_collector_from(rent_collector: &RentCollector, epoch: Epoch) -> RentCollector {
+        rent_collector.clone_with_epoch(epoch)
+    }
+
     fn _new_from_parent(
         parent: &Arc<Bank>,
         collector_id: &Pubkey,
@@ -1636,7 +1640,7 @@ impl Bank {
             slots_per_year: parent.slots_per_year,
             epoch_schedule,
             collected_rent: AtomicU64::new(0),
-            rent_collector: parent.rent_collector.clone_with_epoch(epoch),
+            rent_collector: Self::get_rent_collector_from(&parent.rent_collector, epoch),
             max_tick_height: (slot + 1) * parent.ticks_per_slot,
             block_height: parent.block_height + 1,
             fee_calculator,
@@ -1947,7 +1951,7 @@ impl Bank {
             fee_rate_governor: fields.fee_rate_governor,
             collected_rent: AtomicU64::new(fields.collected_rent),
             // clone()-ing is needed to consider a gated behavior in rent_collector
-            rent_collector: fields.rent_collector.clone_with_epoch(fields.epoch),
+            rent_collector: Self::get_rent_collector_from(&fields.rent_collector, fields.epoch),
             epoch_schedule: fields.epoch_schedule,
             inflation: Arc::new(RwLock::new(fields.inflation)),
             stakes_cache: StakesCache::new(fields.stakes),

runtime/src/rent_collector.rs

@@ -54,7 +54,20 @@ impl RentCollector {
     }
 
     pub fn clone_with_epoch(&self, epoch: Epoch) -> Self {
+        self.clone_with_epoch_and_rate(epoch, self.rent.lamports_per_byte_year)
+    }
+
+    pub fn clone_with_epoch_and_rate(&self, epoch: Epoch, lamports_per_byte_year: u64) -> Self {
+        let rent = if lamports_per_byte_year != self.rent.lamports_per_byte_year {
+            Rent {
+                lamports_per_byte_year,
+                ..self.rent
+            }
+        } else {
+            self.rent
+        };
         Self {
+            rent,
             epoch,
             ..self.clone()
         }