From 5370b9d12eb8bde751a6b9a671f78c53ced4de86 Mon Sep 17 00:00:00 2001
From: Catalin Neagu <neagu.catalin.f@gmail.com>
Date: Thu, 15 Apr 2021 10:22:45 +0300
Subject: [PATCH 1/2] Additional checks for swap in case of admin mistakes

---
 elrond_dex_pair/src/lib.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/elrond_dex_pair/src/lib.rs b/elrond_dex_pair/src/lib.rs
index 2de1831fe..e74748271 100644
--- a/elrond_dex_pair/src/lib.rs
+++ b/elrond_dex_pair/src/lib.rs
@@ -360,6 +360,7 @@ pub trait Pair {
         &self,
         #[payment_token] token_in: TokenIdentifier,
         #[payment] amount_in: BigUint,
+        token_out: TokenIdentifier,
         destination_address: Address,
     ) -> SCResult<()> {
         let caller = self.get_caller();
@@ -378,6 +379,16 @@ pub trait Pair {
 
         let first_token_id = self.liquidity_pool().first_token_id().get();
         let second_token_id = self.liquidity_pool().second_token_id().get();
+        require!(token_in != token_out, "Cannot swap same token");
+        require!(
+            token_in == first_token_id || token_in == second_token_id,
+            "Invalid token in"
+        );
+        require!(
+            token_out == first_token_id || token_out == second_token_id,
+            "Invalid token out"
+        );
+
         let token_out = if token_in == first_token_id {
             second_token_id.clone()
         } else if token_in == second_token_id {
@@ -722,6 +733,7 @@ pub trait Pair {
         );
 
         let mut arg_buffer = ArgBuffer::new();
+        arg_buffer.push_argument_bytes(requested_token.as_esdt_identifier());
         arg_buffer.push_argument_bytes(destination_address.as_bytes());
         self.send().direct_esdt_execute(
             &pair_address,

From ea79bec17843acee596f6a14d7b5ffbe8653ef76 Mon Sep 17 00:00:00 2001
From: Catalin Neagu <neagu.catalin.f@gmail.com>
Date: Thu, 15 Apr 2021 10:29:46 +0300
Subject: [PATCH 2/2] Fix last commit

---
 elrond_dex_pair/src/lib.rs | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/elrond_dex_pair/src/lib.rs b/elrond_dex_pair/src/lib.rs
index e74748271..15131fc5d 100644
--- a/elrond_dex_pair/src/lib.rs
+++ b/elrond_dex_pair/src/lib.rs
@@ -389,13 +389,6 @@ pub trait Pair {
             "Invalid token out"
         );
 
-        let token_out = if token_in == first_token_id {
-            second_token_id.clone()
-        } else if token_in == second_token_id {
-            first_token_id.clone()
-        } else {
-            return sc_error!("Bad token input");
-        };
         let old_k = self.liquidity_pool().calculate_k_for_reserves();
 
         let amount_out = self.liquidity_pool().swap_safe_no_fee(