add subscriber notifications for rollbacks

src/bank.rs

@@ -332,7 +332,25 @@ impl Bank {
         self.last_ids.write().unwrap().checkpoint();
     }
     pub fn rollback(&self) {
+        let rolled_back_pubkeys: Vec<Pubkey> = self
+            .accounts
+            .read()
+            .unwrap()
+            .accounts
+            .keys()
+            .map(|pubkey| pubkey.clone())
+            .collect();
+
         self.accounts.write().unwrap().rollback();
+
+        rolled_back_pubkeys.iter().for_each(|pubkey| {
+            self.accounts
+                .read()
+                .unwrap()
+                .load(&pubkey)
+                .map(|account| self.check_account_subscriptions(&pubkey, account));
+        });
+
         self.last_ids.write().unwrap().rollback();
     }
     pub fn checkpoint_depth(&self) -> usize {
@@ -2187,4 +2205,12 @@ mod tests {
             Err(BankError::DuplicateSignature)
         );
     }
+    #[test]
+    #[should_panic]
+    fn test_rollback_panic() {
+        let alice = Mint::new(10_000);
+        let bank = Bank::new(&alice);
+        bank.rollback();
+    }
+
 }