Make EVM approval max value explicit

Author: gemcoder21

crates/gem_evm/src/encode.rs

@@ -14,7 +14,7 @@ pub fn encode_erc20_transfer(to: &str, amount: &BigInt) -> Result<Vec<u8>, Box<d
     .abi_encode())
 }
 
-pub fn encode_erc20_approve(spender: &str) -> Result<Vec<u8>, Box<dyn Error + Send + Sync>> {
+pub fn encode_erc20_approve_max_value(spender: &str) -> Result<Vec<u8>, Box<dyn Error + Send + Sync>> {
     Ok(IERC20::approveCall {
         spender: Address::from_str(spender)?,
         value: U256::MAX,
@@ -41,3 +41,18 @@ pub fn encode_erc1155_transfer(from: &str, to: &str, token_id: &str) -> Result<V
     }
     .abi_encode())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_encode_erc20_approve_max_value() {
+        let spender = "0x2b5AD5c4795c026514f8317c7a215E218dccD6cF";
+        let data = encode_erc20_approve_max_value(spender).unwrap();
+        let call = IERC20::approveCall::abi_decode(&data).unwrap();
+
+        assert_eq!(call.spender, Address::from_str(spender).unwrap());
+        assert_eq!(call.value, U256::MAX);
+    }
+}

crates/gem_evm/src/provider/preload_mapper.rs

@@ -12,7 +12,7 @@ use primitives::{
     fee::GasPriceType,
 };
 
-use crate::encode::{encode_erc20_approve, encode_erc20_transfer, encode_erc721_transfer, encode_erc1155_transfer};
+use crate::encode::{encode_erc20_approve_max_value, encode_erc20_transfer, encode_erc721_transfer, encode_erc1155_transfer};
 use crate::everstake::{DEFAULT_ALLOWED_INTERCHANGE_NUM, EVERSTAKE_ACCOUNTING_ADDRESS, EVERSTAKE_POOL_ADDRESS, EVERSTAKE_SOURCE, IAccounting, IPool};
 use crate::fee_calculator::FeeCalculator;
 use crate::models::fee::EthereumFeeHistory;
@@ -92,7 +92,11 @@ pub fn get_transaction_params(chain: EVMChain, input: &TransactionLoadInput) ->
         }
         TransactionInputType::Swap(from_asset, _, swap_data) => {
             if let Some(approval) = &swap_data.data.approval {
-                Ok(TransactionParams::new(approval.token.clone(), encode_erc20_approve(&approval.spender)?, BigInt::from(0)))
+                Ok(TransactionParams::new(
+                    approval.token.clone(),
+                    encode_erc20_approve_max_value(&approval.spender)?,
+                    BigInt::from(0),
+                ))
             } else {
                 match from_asset.id.token_subtype() {
                     AssetSubtype::NATIVE => Ok(TransactionParams::new(
@@ -111,7 +115,11 @@ pub fn get_transaction_params(chain: EVMChain, input: &TransactionLoadInput) ->
                 }
             }
         }
-        TransactionInputType::TokenApprove(_, approval) => Ok(TransactionParams::new(approval.token.clone(), encode_erc20_approve(&approval.spender)?, BigInt::from(0))),
+        TransactionInputType::TokenApprove(_, approval) => Ok(TransactionParams::new(
+            approval.token.clone(),
+            encode_erc20_approve_max_value(&approval.spender)?,
+            BigInt::from(0),
+        )),
         TransactionInputType::Generic(_, _, extra) => Ok(TransactionParams::new(
             extra.to.clone(),
             extra.data.clone().unwrap_or_default(),
@@ -150,7 +158,7 @@ pub fn get_transaction_params(chain: EVMChain, input: &TransactionLoadInput) ->
         },
         TransactionInputType::Earn(_, _, earn_data) => {
             if let Some(approval) = &earn_data.approval {
-                Ok(TransactionParams::new_approval(approval.token.clone(), encode_erc20_approve(&approval.spender)?))
+                Ok(TransactionParams::new_approval(approval.token.clone(), encode_erc20_approve_max_value(&approval.spender)?))
             } else {
                 Ok(TransactionParams::new(
                     earn_data.contract_address.clone(),

crates/gem_evm/src/signer/chain_signer.rs

@@ -8,7 +8,7 @@ use primitives::{ChainSigner, EVMChain, NFTType, SignerError, SignerInput, Stake
 
 use super::model::TransactionParams;
 use super::sign_eip1559_tx;
-use crate::encode::{encode_erc20_approve, encode_erc20_transfer, encode_erc721_transfer, encode_erc1155_transfer};
+use crate::encode::{encode_erc20_approve_max_value, encode_erc20_transfer, encode_erc721_transfer, encode_erc1155_transfer};
 
 #[allow(dead_code)]
 pub struct EvmChainSigner {
@@ -53,7 +53,7 @@ impl ChainSigner for EvmChainSigner {
         let params = TransactionParams::from_input(input)?;
         let approval = input.input_type.get_approval_data()?;
         sign_and_encode(
-            &build_eip1559_transaction(&params, &approval.token, U256::ZERO, Bytes::from(encode_erc20_approve(&approval.spender)?))?,
+            &build_eip1559_transaction(&params, &approval.token, U256::ZERO, Bytes::from(encode_erc20_approve_max_value(&approval.spender)?))?,
             private_key,
         )
     }
@@ -187,7 +187,7 @@ fn sign_contract_call(
     let params = TransactionParams::from_input(input)?;
 
     if let Some(approval) = approval {
-        let approval_transaction = build_eip1559_transaction(&params, &approval.token, U256::ZERO, Bytes::from(encode_erc20_approve(&approval.spender)?))?;
+        let approval_transaction = build_eip1559_transaction(&params, &approval.token, U256::ZERO, Bytes::from(encode_erc20_approve_max_value(&approval.spender)?))?;
         let main_params = TransactionParams {
             nonce: params.nonce + 1,
             gas_limit,

crates/yielder/src/yo/client.rs

@@ -86,12 +86,7 @@ impl YoGatewayClient {
         let allowance = self.ethereum_client.call_contract(token, IERC20::allowanceCall { owner, spender }).await?;
 
         if allowance < amount {
-            Ok(Some(ApprovalData {
-                token: token.to_string(),
-                spender: spender.to_string(),
-                value: amount.to_string(),
-                is_unlimited: false,
-            }))
+            Ok(Some(build_token_approval_data(token, spender, amount)))
         } else {
             Ok(None)
         }
@@ -111,6 +106,15 @@ fn convert_to_assets_ceil(shares: U256, total_assets: U256, total_supply: U256)
     (shares * total_assets + total_supply - U256::from(1)) / total_supply
 }
 
+fn build_token_approval_data(token: Address, spender: Address, amount: U256) -> ApprovalData {
+    ApprovalData {
+        token: token.to_string(),
+        spender: spender.to_string(),
+        value: amount.to_string(),
+        is_unlimited: true,
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -126,4 +130,21 @@ mod tests {
         assert_eq!(convert_to_assets_ceil(U256::from(100), U256::from(1000), U256::ZERO), U256::ZERO);
         assert_eq!(convert_to_assets_ceil(U256::ZERO, U256::ZERO, U256::ZERO), U256::ZERO);
     }
+
+    #[test]
+    fn test_build_token_approval_data() {
+        let token = Address::from([1; 20]);
+        let spender = Address::from([2; 20]);
+        let amount = U256::from(1234);
+
+        assert_eq!(
+            build_token_approval_data(token, spender, amount),
+            ApprovalData {
+                token: token.to_string(),
+                spender: spender.to_string(),
+                value: "1234".to_string(),
+                is_unlimited: true,
+            }
+        );
+    }
 }