Prevent underflow in Amount

rust/src/base/amount.rs

@@ -5,6 +5,7 @@ use crate::{
     utility::functions::nanomina_to_mina,
 };
 use anyhow::anyhow;
+use log::error;
 use rust_decimal::Decimal;
 use serde::{Deserialize, Serialize};
 use std::ops::{Add, AddAssign, Sub, SubAssign};
@@ -58,6 +59,9 @@ impl Add<i64> for Amount {
         let abs = rhs.unsigned_abs();
 
         if rhs < 0 {
+            if self.0 < abs {
+                panic!("Amount: u64 underflow in Add<i64>")
+            }
             Self(self.0 - abs)
         } else {
             Self(self.0 + abs)
@@ -66,18 +70,15 @@ impl Add<i64> for Amount {
 }
 
 impl Sub<Amount> for Amount {
-    type Output = Amount;
+    type Output = Option<Amount>;
 
     fn sub(self, rhs: Amount) -> Self::Output {
-        Self(self.0.saturating_sub(rhs.0))
-    }
-}
-
-impl Sub<u64> for Amount {
-    type Output = Amount;
-
-    fn sub(self, rhs: u64) -> Self::Output {
-        Self(self.0 - rhs)
+        if self.0 < rhs.0 {
+            error!("Underflow in Sub<Amount>: self.0: {} rhs.0: {}", self.0, rhs.0);
+            None
+        } else {
+            Some(Self(self.0 - rhs.0))
+        }
     }
 }
 
@@ -98,6 +99,9 @@ impl AddAssign<i64> for Amount {
         let abs = rhs.unsigned_abs();
 
         if rhs < 0 {
+            if self.0 < abs {
+                panic!("Underflow in AddAssign<i64>")
+            }
             *self -= abs;
         } else {
             *self += abs;
@@ -107,6 +111,9 @@ impl AddAssign<i64> for Amount {
 
 impl SubAssign<u64> for Amount {
     fn sub_assign(&mut self, rhs: u64) {
+        if self.0 < rhs {
+            panic!("Underflow in SubAssign<u64>")
+        }
         *self = Self(self.0 - rhs)
     }
 }
@@ -118,6 +125,9 @@ impl SubAssign<i64> for Amount {
         if rhs < 0 {
             *self += abs;
         } else {
+            if self.0 < abs {
+                panic!("Underflow in SubAssign<i64>")
+            }
             *self -= abs;
         }
     }

rust/src/block/precomputed/mod.rs

@@ -319,9 +319,9 @@ impl PrecomputedBlock {
         // maybe coinbase receiver
         if let Some(bal) = self.coinbase_receiver_balance() {
             if [
-                (Amount(MAINNET_COINBASE_REWARD) - MAINNET_ACCOUNT_CREATION_FEE).0,
+                Amount(MAINNET_COINBASE_REWARD - MAINNET_ACCOUNT_CREATION_FEE_U64).0,
                 // supercharged
-                (Amount(2 * MAINNET_COINBASE_REWARD) - MAINNET_ACCOUNT_CREATION_FEE).0,
+                Amount(2 * MAINNET_COINBASE_REWARD - MAINNET_ACCOUNT_CREATION_FEE_U64).0,
             ]
             .contains(&bal)
             {

rust/src/constants.rs

@@ -27,8 +27,9 @@ pub const MINA_TOKEN_ID: u64 = 1;
 
 pub const MAINNET_BLOCK_SLOT_TIME_MILLIS: u64 = 180000;
 pub const MAINNET_TRANSITION_FRONTIER_K: u32 = 290;
-pub const MAINNET_ACCOUNT_CREATION_FEE: Amount = Amount(1e9 as u64);
-pub const MAINNET_COINBASE_REWARD: u64 = 720000000000;
+pub const MAINNET_ACCOUNT_CREATION_FEE_U64: u64 = 1e9 as u64;
+pub const MAINNET_ACCOUNT_CREATION_FEE: Amount = Amount(MAINNET_ACCOUNT_CREATION_FEE_U64);
+pub const MAINNET_COINBASE_REWARD: u64 = 720_000_000_000;
 
 pub const MAINNET_GENESIS_HASH: &str = "3NKeMoncuHab5ScarV5ViyF16cJPT4taWNSaTLS64Dp67wuXigPZ";
 pub const MAINNET_GENESIS_PREV_STATE_HASH: &str =

rust/src/ledger/account/mod.rs

@@ -108,7 +108,9 @@ impl Account {
             && !self.created_by_zkapp
         {
             return Self {
-                balance: self.balance - MAINNET_ACCOUNT_CREATION_FEE,
+                // TODO:
+                // balance: (self.balance - MAINNET_ACCOUNT_CREATION_FEE).unwrap_or_else(|| panic!("Underflow in Account::display. pk: {:?}", self.public_key)),
+                balance: (self.balance - MAINNET_ACCOUNT_CREATION_FEE).unwrap_or(Amount(0)),
                 ..self
             };
         }
@@ -183,7 +185,7 @@ impl Account {
     /// Unapply a coinbase
     pub fn coinbase_unapply(self, diff: &CoinbaseDiff) -> Self {
         Self {
-            balance: self.balance - diff.amount,
+            balance: (self.balance - diff.amount).unwrap_or_else(|| panic!("Underflow in coinbase_unapply. CoinbaseDiff: {:?}", diff)),
             ..self
         }
     }
@@ -219,7 +221,7 @@ impl Account {
     pub fn payment_unapply(self, diff: &PaymentDiff) -> Self {
         match diff.update_type {
             UpdateType::Credit => Self {
-                balance: self.balance - diff.amount,
+                balance: (self.balance - diff.amount).unwrap_or_else(|| panic!("Underflow in payment_unapply. PaymentDiff: {:?}", diff)),
                 ..self
             },
             UpdateType::Debit(nonce) => Self {
@@ -253,7 +255,8 @@ impl Account {
     /// balance.
     fn debit(self, amount: Amount, nonce: Option<Nonce>) -> Self {
         Self {
-            balance: self.balance - amount,
+            balance: (self.balance - amount).unwrap_or_else(||
+                panic!("Underflow in Account::debit. pk: {} balance: {} amount: {}", self.public_key, self.balance, amount)),
             nonce: nonce.or(self.nonce),
             ..self
         }
@@ -825,7 +828,7 @@ mod tests {
         assert_eq!(
             after,
             Account {
-                balance: before.balance - amount,
+                balance: (before.balance - amount).unwrap_or_else(|| panic!("Underflow in zkapp_account_diff_payment. pk: {}", pk)),
                 ..before
             }
         );