From b3d2012e0fea85d681fc18c2bcb049b2cdc0160e Mon Sep 17 00:00:00 2001
From: Yan Liu <yanliu8@proton.me>
Date: Wed, 29 Jan 2025 23:15:04 +0100
Subject: [PATCH] fix(ledger): Make the transfer fee optional

---
 ic-canister/src/canister_backend/icrc1.rs |  2 +-
 ic-canister/tests/test_icrc1.rs           | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/ic-canister/src/canister_backend/icrc1.rs b/ic-canister/src/canister_backend/icrc1.rs
index d228ca6..df88385 100644
--- a/ic-canister/src/canister_backend/icrc1.rs
+++ b/ic-canister/src/canister_backend/icrc1.rs
@@ -191,7 +191,7 @@ pub fn _icrc1_transfer(arg: TransferArg) -> Result<Nat, Icrc1TransferError> {
     let to: IcrcCompatibleAccount = arg.to.into();
 
     LEDGER_MAP.with(|ledger| {
-        let fee = nat_to_balance(&arg.fee.unwrap_or_default());
+        let fee = nat_to_balance(&arg.fee.unwrap_or(Nat::from(DC_TOKEN_TRANSFER_FEE_E9S)));
         let balance_to_after: TokenAmountE9s = if to.is_minting_account() {
             if fee != 0 {
                 return Err(Icrc1TransferError::BadFee {
diff --git a/ic-canister/tests/test_icrc1.rs b/ic-canister/tests/test_icrc1.rs
index c875be4..e1b4205 100644
--- a/ic-canister/tests/test_icrc1.rs
+++ b/ic-canister/tests/test_icrc1.rs
@@ -415,6 +415,26 @@ fn test_fee_handling() {
         Result<Nat, TransferError>
     );
     assert!(result.is_ok());
+
+    // Test with no fee
+    let transfer_arg = TransferArg {
+        from_subaccount: None,
+        to,
+        amount: 1_000_000u64.into(),
+        fee: None,
+        created_at_time: Some(ts),
+        memo: None,
+    };
+
+    let result = update_check_and_decode!(
+        ctx.pic,
+        ctx.canister_id,
+        from.owner,
+        "icrc1_transfer",
+        candid::encode_one(transfer_arg).unwrap(),
+        Result<Nat, TransferError>
+    );
+    assert!(result.is_ok());
 }
 
 #[test]