fix: evmCoinInfo not exists in historical state (cosmos#790)

* Problem: evmCoinInfo not exists in historical state (cosmos#16)

* support default evmCoinInfo

* changelog

* Update CHANGELOG.md

---------

Co-authored-by: Alex | Cosmos Labs <[email protected]>

Author: yihuang

CHANGELOG.md

@@ -22,6 +22,7 @@
 - [\#756](https://github.com/cosmos/evm/pull/756) Fix error message typo in NewMsgCancelProposal.
 - [\#772](https://github.com/cosmos/evm/pull/772) Avoid panic on close if evm mempool not used.
 - [\#774](https://github.com/cosmos/evm/pull/774) Emit proper allowance amount in erc20 event.
+- [\#790](https://github.com/cosmos/evm/pull/790) fix panic in historical query due to missing EvmCoinInfo.
 
 ## v0.5.0
 

x/vm/keeper/coin_info.go

@@ -56,7 +56,7 @@ func (k Keeper) GetEvmCoinInfo(ctx sdk.Context) (coinInfo types.EvmCoinInfo) {
 	store := ctx.KVStore(k.storeKey)
 	bz := store.Get(types.KeyPrefixEvmCoinInfo)
 	if bz == nil {
-		return coinInfo
+		return k.defaultEvmCoinInfo
 	}
 	k.cdc.MustUnmarshal(bz, &coinInfo)
 	return

x/vm/keeper/keeper.go

@@ -85,6 +85,10 @@ type Keeper struct {
 	// virtualFeeCollection enabling will use "Virtual" methods from the bank module to accumulate
 	// fees to the fee collector module in the endBlocker instead of using regular sends during tx execution.
 	virtualFeeCollection bool
+
+	// defaultEvmCoinInfo is the default EVM coin info used when evmCoinInfo is not initialized in the state,
+	// mainly for historical queries.
+	defaultEvmCoinInfo types.EvmCoinInfo
 }
 
 // NewKeeper generates new evm module keeper
@@ -154,6 +158,12 @@ func (k Keeper) Logger(ctx sdk.Context) log.Logger {
 	return ctx.Logger().With("module", types.ModuleName)
 }
 
+// WithDefaultEvmCoinInfo set default EvmCoinInfo
+func (k *Keeper) WithDefaultEvmCoinInfo(coinInfo types.EvmCoinInfo) *Keeper {
+	k.defaultEvmCoinInfo = coinInfo
+	return k
+}
+
 // ----------------------------------------------------------------------------
 // Block Bloom
 // Required by Web3 API.