solana: fix carping constraint (#171)

Co-authored-by: A5 Pickle <a5-pickle@users.noreply.github.com>

Author: a5-pickle

solana/programs/matching-engine/src/events/auction_updated.rs

@@ -16,5 +16,5 @@ pub struct AuctionUpdated {
     pub token_balance_before: u64,
     pub amount_in: u64,
     pub total_deposit: u64,
-    pub max_offer_price_allowed: u64,
+    pub max_offer_price_allowed: Option<u64>,
 }

solana/programs/matching-engine/src/processor/auction/offer/improve.rs

@@ -31,7 +31,7 @@ pub struct ImproveOffer<'info> {
 
             require!(
                 offer_price
-                    <= utils::auction::compute_min_allowed_offer(&active_auction.config, info),
+                    < utils::auction::compute_min_allowed_offer(&active_auction.config, info),
                 MatchingEngineError::CarpingNotAllowed
             );
 
@@ -144,7 +144,8 @@ pub fn improve_offer(ctx: Context<ImproveOffer>, offer_price: u64) -> Result<()>
             token_balance_before: offer_token.amount,
             amount_in: info.amount_in,
             total_deposit: info.total_deposit(),
-            max_offer_price_allowed: utils::auction::compute_min_allowed_offer(config, info),
+            max_offer_price_allowed: utils::auction::compute_min_allowed_offer(config, info)
+                .checked_sub(1),
         });
     }
 

solana/programs/matching-engine/src/processor/auction/offer/place_initial/cctp.rs

@@ -177,7 +177,8 @@ pub fn place_initial_offer_cctp(
         token_balance_before: ctx.accounts.offer_token.amount,
         amount_in,
         total_deposit: info.total_deposit(),
-        max_offer_price_allowed: utils::auction::compute_min_allowed_offer(config, info),
+        max_offer_price_allowed: utils::auction::compute_min_allowed_offer(config, info)
+            .checked_sub(1),
     });
 
     // Finally transfer tokens from the offer authority's token account to the

solana/ts/src/idl/json/matching_engine.json

@@ -3580,7 +3580,9 @@
           },
           {
             "name": "max_offer_price_allowed",
-            "type": "u64"
+            "type": {
+              "option": "u64"
+            }
           }
         ]
       }

solana/ts/src/idl/ts/matching_engine.ts

@@ -3586,7 +3586,9 @@ export type MatchingEngine = {
           },
           {
             "name": "maxOfferPriceAllowed",
-            "type": "u64"
+            "type": {
+              "option": "u64"
+            }
           }
         ]
       }

solana/ts/src/matchingEngine/index.ts

@@ -158,7 +158,7 @@ export type AuctionUpdated = {
     tokenBalanceBefore: BN;
     amountIn: BN;
     totalDeposit: BN;
-    maxOfferPriceAllowed: BN;
+    maxOfferPriceAllowed: BN | null;
 };
 
 export type OrderExecuted = {
@@ -2525,7 +2525,7 @@ export class MatchingEngineProgram {
 
     async computeMinOfferDelta(offerPrice: Uint64): Promise<bigint> {
         const { minOfferDeltaBps } = await this.fetchAuctionParameters();
-        return (uint64ToBigInt(offerPrice) * BigInt(minOfferDeltaBps)) / FEE_PRECISION_MAX;
+        return (uint64ToBigInt(offerPrice) * BigInt(minOfferDeltaBps)) / FEE_PRECISION_MAX + 1n;
     }
 
     async computeNotionalSecurityDeposit(amountIn: Uint64, configId?: number) {