fix: spot calculate fee on amend, use order price if no amended price…

… is provided

Signed-off-by: Jeremy Letang <[email protected]>

CHANGELOG.md

@@ -22,9 +22,9 @@
 - [11535](https://github.com/vegaprotocol/vega/issues/11535) - Added support for lottery rank distribution strategy.
 - [11536](https://github.com/vegaprotocol/vega/issues/11536) - Make the batch market instructions errors programmatically usable.
 - [11546](https://github.com/vegaprotocol/vega/issues/11546) - Add validation to market proposals metadata.
-- [11562](https://github.com/vegaprotocol/vega/issues/11562) - Update average notional metric with mark price at the end of the epoch and when calculating live score. 
+- [11562](https://github.com/vegaprotocol/vega/issues/11562) - Update average notional metric with mark price at the end of the epoch and when calculating live score.
 - [11570](https://github.com/vegaprotocol/vega/issues/11570) - Include the required set of parties for evaluation for eligible entities reward.
-  
+
 ### 🐛 Fixes
 
 - [11521](https://github.com/vegaprotocol/vega/issues/11521) - Restore `AMM` position factor when loading from a snapshot.
@@ -35,6 +35,7 @@
 - [11540](https://github.com/vegaprotocol/vega/issues/11540) - Fix spam check for spots to use not double count quantum.
 - [11542](https://github.com/vegaprotocol/vega/issues/11542) - Fix non determinism in lottery ranking.
 - [11544](https://github.com/vegaprotocol/vega/issues/11544) - Fix empty candles stream.
+- [11579](https://github.com/vegaprotocol/vega/issues/11579) - Spot calculate fee on amend, use order price if no amended price is provided.
 
 
 ## 0.77.5

core/execution/spot/market.go

@@ -2380,13 +2380,13 @@ func (m *Market) validateOrderAmendment(order *types.Order, amendment *types.Ord
 		existingHoldingQty, existingHoldingFee := m.orderHoldingTracker.GetCurrentHolding(order.ID)
 		oldHoldingRequirement := num.Sum(existingHoldingQty, existingHoldingFee)
 		newFeesRequirement := num.UintZero()
-		if m.as.InAuction() {
-			newFeesRequirement, _ = m.calculateFees(order.Party, remaining, amendment.Price, order.Side)
-		}
 		price := order.Price
 		if amendment.Price != nil {
 			price, _ = num.UintFromDecimal(amendment.Price.ToDecimal().Mul(m.priceFactor))
 		}
+		if m.as.InAuction() {
+			newFeesRequirement, _ = m.calculateFees(order.Party, remaining, price, order.Side)
+		}
 		if order.PeggedOrder != nil {
 			p, err := m.getNewPeggedPrice(order)
 			if err != nil {