program: account for reduce only when checking margin in trigger order

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixes
 
+- program: account for reduce only when checking margin in trigger order ([#583](https://github.com/drift-labs/protocol-v2/pull/583))
+
 ### Breaking
 
 ## [2.38.0] - 2023-08-25

programs/drift/src/controller/orders.rs

@@ -293,15 +293,17 @@ pub fn place_perp_order(
         user.perp_positions[position_index].worst_case_base_asset_amount()?;
 
     let position_base_asset_amount = user.perp_positions[position_index].base_asset_amount;
-    let order_risk_reducing = is_order_risk_decreasing(
+    let base_asset_amount_unfilled = user.orders[new_order_index]
+        .get_base_asset_amount_unfilled(Some(position_base_asset_amount))?;
+    let order_risk_decreasing = is_order_risk_decreasing(
         &params.direction,
-        order_base_asset_amount,
+        base_asset_amount_unfilled,
         position_base_asset_amount,
     )?;
 
     let risk_decreasing = worst_case_base_asset_amount_after.unsigned_abs()
         <= worst_case_base_asset_amount_before.unsigned_abs()
-        && order_risk_reducing;
+        && order_risk_decreasing;
 
     // when orders are placed in bulk, only need to check margin on last place
     if options.enforce_margin_check {
@@ -2549,12 +2551,13 @@ pub fn trigger_order(
 
     drop(perp_market);
 
-    // If order is risk increasing and user is below initial margin, cancel it
+    // If order is position reducing and user is below initial margin, cancel it
     let order_direction = user.orders[order_index].direction;
-    let order_base_asset_amount = user.orders[order_index].base_asset_amount;
     let position_base_asset_amount = user
         .force_get_perp_position_mut(market_index)?
         .base_asset_amount;
+    let order_base_asset_amount = user.orders[order_index]
+        .get_base_asset_amount_unfilled(Some(position_base_asset_amount))?;
     let is_risk_increasing = is_order_risk_increasing(
         &order_direction,
         order_base_asset_amount,
@@ -2982,8 +2985,14 @@ pub fn place_spot_order(
     let (worst_case_token_amount_after, _) = user.spot_positions[spot_position_index]
         .get_worst_case_token_amount(spot_market, &oracle_price_data, None, None)?;
 
-    let order_risk_decreasing =
-        is_spot_order_risk_decreasing(&user.orders[new_order_index], &balance_type, token_amount)?;
+    let order_direction = user.orders[new_order_index].direction;
+    let base_asset_amount_unfilled = user.orders[new_order_index]
+        .get_base_asset_amount_unfilled(Some(signed_token_amount.cast()?))?;
+    let order_risk_decreasing = is_order_risk_decreasing(
+        &order_direction,
+        base_asset_amount_unfilled,
+        signed_token_amount.cast()?,
+    )?;
 
     // Order fails if it's risk increasing and it brings the user collateral below the margin requirement
     let risk_decreasing = worst_case_token_amount_after.unsigned_abs()
@@ -4484,15 +4493,22 @@ pub fn trigger_spot_order(
     emit!(order_action_record);
 
     let position_index = user.get_spot_position_index(market_index)?;
-    let token_amount = user.spot_positions[position_index].get_token_amount(&spot_market)?;
+    let signed_token_amount = user.spot_positions[position_index]
+        .get_signed_token_amount(&spot_market)?
+        .cast::<i64>()?;
 
     drop(spot_market);
     drop(quote_market);
 
-    // If order is risk increasing and user is below initial margin, cancel it
-    let balance_type = user.spot_positions[position_index].balance_type;
-    let is_risk_increasing =
-        is_spot_order_risk_increasing(&user.orders[order_index], &balance_type, token_amount)?;
+    // If order is position increasing and user is below initial margin, cancel it
+    let direction = user.orders[order_index].direction;
+    let order_base_asset_amount_unfilled =
+        user.orders[order_index].get_base_asset_amount_unfilled(Some(signed_token_amount))?;
+    let is_risk_increasing = is_order_risk_increasing(
+        &direction,
+        order_base_asset_amount_unfilled,
+        signed_token_amount,
+    )?;
 
     let meets_initial_margin_requirement =
         meets_initial_margin_requirement(user, perp_market_map, spot_market_map, oracle_map)?;

programs/drift/src/math/orders.rs

@@ -29,7 +29,7 @@ use crate::state::oracle::OraclePriceData;
 use crate::state::oracle_map::OracleMap;
 use crate::state::perp_market::{PerpMarket, AMM};
 use crate::state::perp_market_map::PerpMarketMap;
-use crate::state::spot_market::{SpotBalanceType, SpotMarket};
+use crate::state::spot_market::SpotMarket;
 use crate::state::spot_market_map::SpotMarketMap;
 use crate::state::user::{
     MarketType, Order, OrderStatus, OrderTriggerCondition, PerpPosition, User,
@@ -583,33 +583,6 @@ pub fn order_satisfies_trigger_condition(order: &Order, oracle_price: u64) -> Dr
     }
 }
 
-pub fn is_spot_order_risk_decreasing(
-    order: &Order,
-    balance_type: &SpotBalanceType,
-    token_amount: u128,
-) -> DriftResult<bool> {
-    let risk_decreasing = match (balance_type, order.direction) {
-        (SpotBalanceType::Deposit, PositionDirection::Short) => {
-            (order.base_asset_amount as u128) < token_amount.safe_mul(2)?
-        }
-        (SpotBalanceType::Borrow, PositionDirection::Long) => {
-            (order.base_asset_amount as u128) < token_amount.safe_mul(2)?
-        }
-        (_, _) => false,
-    };
-
-    Ok(risk_decreasing)
-}
-
-pub fn is_spot_order_risk_increasing(
-    order: &Order,
-    balance_type: &SpotBalanceType,
-    token_amount: u128,
-) -> DriftResult<bool> {
-    is_spot_order_risk_decreasing(order, balance_type, token_amount)
-        .map(|risk_decreasing| !risk_decreasing)
-}
-
 pub fn is_order_risk_decreasing(
     order_direction: &PositionDirection,
     order_base_asset_amount: u64,