properly keeping track of availible amount when redeeming fees

solendprotocol · Jun 2, 2022 · 2901de9 · 2901de9
1 parent d532f16
commit 2901de9
Show file tree

Hide file tree

Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/token-lending/program/src/processor.rs b/token-lending/program/src/processor.rs
@@ -28,7 +28,7 @@ use solana_program::{
 };
 use spl_token::solana_program::instruction::AccountMeta;
 use spl_token::state::{Account, Mint};
-use std::{convert::TryInto, result::Result};
+use std::{convert::TryInto, result::Result, cmp::min};
 use switchboard_program::{
     get_aggregator, get_aggregator_result, AggregatorState, RoundResult, SwitchboardAccountType,
 };
@@ -2256,16 +2256,21 @@ fn process_redeem_fees(program_id: &Pubkey, accounts: &[AccountInfo]) -> Program
         return Err(LendingError::InvalidMarketAuthority.into());
     }
 
-    let fee_receiver_claimable_amount = reserve
+    let mut fee_receiver_claimable_amount = reserve
         .liquidity
         .accumulated_protocol_fees_wads
         .try_floor_u64()?;
 
+    fee_receiver_claimable_amount = min(fee_receiver_claimable_amount, reserve.liquidity.available_amount);
+
     reserve.liquidity.accumulated_protocol_fees_wads = reserve
         .liquidity
         .accumulated_protocol_fees_wads
         .try_sub(Decimal::from(fee_receiver_claimable_amount))?;
 
+    // for accounting purposes we need to subtract from availible amount and add to borrowed amount
+    reserve.liquidity.borrow(Decimal::from(fee_receiver_claimable_amount))?;
+
     Reserve::pack(reserve, &mut reserve_info.data.borrow_mut())?;
 
     spl_token_transfer(TokenTransferParams {

diff --git a/token-lending/program/tests/redeem_fees.rs b/token-lending/program/tests/redeem_fees.rs
@@ -192,8 +192,18 @@ async fn test_success() {
         .unwrap();
     let new_borrow_amount_wads = Decimal::from(BORROW_AMOUNT)
         .try_add(delta_borrowed_amount_wads)
+        .unwrap()
+        .try_add(Decimal::from(usdc_balance_after - usdc_balance_before))
         .unwrap();
 
+    assert_eq!(
+        usdc_reserve_before.liquidity.total_supply(),
+        usdc_reserve.liquidity.total_supply(),
+    );
+    assert_eq!(
+        sol_reserve_before.liquidity.total_supply(),
+        sol_reserve.liquidity.total_supply(),
+    );
     assert_eq!(
         sol_reserve.liquidity.cumulative_borrow_rate_wads,
         compound_rate.into()