Better error message in EVMTokenConnectors.Sink.depositCapacity() regarding insufficient bridging fees

Author: m-Peter

cadence/contracts/connectors/evm/ERC4626SinkConnectors.cdc

@@ -132,11 +132,11 @@ access(all) contract ERC4626SinkConnectors {
             // approve the ERC4626 vault to spend the assets on deposit
             let uintAmount = FlowEVMBridgeUtils.convertCadenceAmountToERC20Amount(amount, erc20Address: self.assetEVMAddress)
             let approveRes = self._call(
-                    to: self.assetEVMAddress,
-                    signature: "approve(address,uint256)",
-                    args: [self.vault, uintAmount],
-                    gasLimit: 500_000
-                )!
+                to: self.assetEVMAddress,
+                signature: "approve(address,uint256)",
+                args: [self.vault, uintAmount],
+                gasLimit: 500_000
+            )!
             if approveRes.status != EVM.Status.successful {
                 // Cadence panic reverts all EVM state changes in this transaction, so no need to bridge token back.
                 panic(self._approveErrorMessage(ufixAmount: amount, uintAmount: uintAmount, approveRes: approveRes))

cadence/contracts/connectors/evm/EVMTokenConnectors.cdc

@@ -125,9 +125,11 @@ access(all) contract EVMTokenConnectors {
 
             // collect VM bridge fees
             let feeAmount = FlowEVMBridgeConfig.baseFee
-            if self.feeSource.minimumAvailable() < feeAmount {
-                return // early return here instead of reverting in bridge scope on insufficient fees
-            }
+            let availableFees = self.feeSource.minimumAvailable()
+            assert(
+                availableFees >= feeAmount,
+                message: "Fee source \(availableFees.toString()) cannot cover bridging base fee \(feeAmount.toString())"
+            )
             let fees <- self.feeSource.withdrawAvailable(maxAmount: feeAmount)
 
             // deposit tokens and handle remaining fees