Merge pull request #3237 from jorgemmsilva/fix/decimals-migration-nil…

…-uint64

fix: decimals migration - skip accounts with no base tokens

packages/vm/core/migrations/m001/decimals_migration.go

@@ -15,7 +15,11 @@ var AccountDecimals = migrations.Migration{
 		migrateBaseTokens := func(accKey []byte) {
 			// converts an account base token balance from uint64 to big.Int (while changing the decimals from 6 to 18)
 			key := accounts.BaseTokensKey(kv.Key(accKey))
-			amount := codec.MustDecodeUint64(state.Get(key))
+			amountBytes := state.Get(key)
+			if amountBytes == nil {
+				return
+			}
+			amount := codec.MustDecodeUint64(amountBytes)
 			amountMigrated := util.MustBaseTokensDecimalsToEthereumDecimalsExact(amount, 6)
 			state.Set(key, codec.EncodeBigIntAbs(amountMigrated))
 		}