refactor: make erc20keeper optional in x/vm (#609)

* imp: make erc20keeper optional in x/vm

* add changelog

---------

Co-authored-by: Vlad J <[email protected]>

Author: gjermundgaraba

CHANGELOG.md

@@ -30,6 +30,7 @@
 - [\#582](https://github.com/cosmos/evm/pull/582) Add block max-gas (from genesis.json) and new min-tip (from app.toml/flags) ingestion into mempool config
 - [\#598](https://github.com/cosmos/evm/pull/598) Reduce number of times CreateQueryContext in mempool.
 - [\#606](https://github.com/cosmos/evm/pull/606) Regenerate mock file for bank keeper related test.
+- [\#609](https://github.com/cosmos/evm/pull/609) Make `erc20Keeper` optional in the EVM keeper
 - [\#624](https://github.com/cosmos/evm/pull/624) Cleanup unnecessary `fix-revert-gas-refund-height`.
 - [\#635](https://github.com/cosmos/evm/pull/635) Move DefaultStaticPrecompiles to /evm and allow projects to set it by default alongside the keeper.
 

x/vm/keeper/keeper.go

@@ -59,7 +59,7 @@ type Keeper struct {
 	stakingKeeper types.StakingKeeper
 	// fetch EIP1559 base fee and parameters
 	feeMarketWrapper *wrappers.FeeMarketWrapper
-	// erc20Keeper interface needed to instantiate erc20 precompiles
+	// optional erc20Keeper interface needed to instantiate erc20 precompiles
 	erc20Keeper types.Erc20Keeper
 	// consensusKeeper is used to get consensus params during query contexts.
 	// This is needed as block.gasLimit is expected to be available in eth_call, which is routed through Cosmos SDK's

x/vm/keeper/precompiles.go

@@ -33,6 +33,11 @@ func (k *Keeper) GetPrecompileInstance(
 		}, found, nil
 	}
 
+	// Since erc20Keeper is optional, we check if it is nil, in which case we just return that we didn't find the precompile
+	if k.erc20Keeper == nil {
+		return nil, false, nil
+	}
+
 	// Get the precompile from the dynamic precompiles
 	precompile, found, err := k.erc20Keeper.GetERC20PrecompileInstance(ctx, address)
 	if err != nil || !found {