doc: document changes in code

Signed-off-by: Francisco de Borja Aranda Castillejo <[email protected]>

x/evm/keeper/keeper.go

@@ -41,6 +41,7 @@ import (
 // CustomContractFn defines a custom precompiled contract generator with ctx, rules and returns a precompiled contract.
 type CustomContractFn func(sdk.Context, params.Rules) vm.PrecompiledContract
 
+// EventConverter type represents a function that parses a list of EventAttributes to a list of Ethereum Log objects.
 type EventConverter = func([]abci.EventAttribute) []*ethtypes.Log
 
 // Keeper grants access to the EVM module state and implements the go-ethereum StateDB interface.
@@ -78,7 +79,9 @@ type Keeper struct {
 	hooks types.EvmHooks
 
 	// Legacy subspace
-	ss                paramstypes.Subspace
+	ss paramstypes.Subspace
+
+	// customContractFns is the list of precompiled stateful contract functions.
 	customContractFns []CustomContractFn
 
 	ck consensusparamkeeper.Keeper

x/evm/keeper/state_transition.go

@@ -70,25 +70,41 @@ func (k *Keeper) NewEVM(
 	if tracer == nil {
 		tracer = k.Tracer(ctx, msg, cfg.ChainConfig)
 	}
+
 	vmConfig := k.VMConfig(ctx, msg, cfg, tracer)
 	rules := cfg.ChainConfig.Rules(big.NewInt(ctx.BlockHeight()), cfg.ChainConfig.MergeNetsplitBlock != nil)
 	contracts := make(map[common.Address]vm.PrecompiledContract)
 	active := make([]common.Address, 0)
+
+	// Creates the list of **default** precompiled contracts (not stateful) for this set of rules.
+	// contracts hold the list of all contracts, while active holds the list of all active addresses.
+	// i.e create the list of contracts for Berlin.
 	for addr, c := range vm.DefaultPrecompiles(rules) {
 		contracts[addr] = c
 		active = append(active, addr)
 	}
+
+	// Add the custom stateful precompiled contracts and their addresses to the list.
+	// Then, mark them as active.
 	for _, fn := range k.customContractFns {
 		c := fn(ctx, rules)
 		addr := c.Address()
 		contracts[addr] = c
 		active = append(active, addr)
 	}
+
+	// Sort the active slice in address ascending order.
 	sort.SliceStable(active, func(i, j int) bool {
 		return bytes.Compare(active[i].Bytes(), active[j].Bytes()) < 0
 	})
+
 	evm := vm.NewEVM(blockCtx, txCtx, stateDB, cfg.ChainConfig, vmConfig)
+
+	// Set the precompiled contracts:
+	// - contracts contains all the contracts.
+	// - active contains the addresses of the active contracts.
 	evm.WithPrecompiles(contracts, active)
+
 	return evm
 }
 

x/evm/statedb/statedb.go

@@ -33,6 +33,7 @@ import (
 
 const StateDBContextKey = "statedb"
 
+// EventConverter represents a function able to parse a sdk.Event into an ethtypes.Log.
 type EventConverter = func(sdk.Event) (*ethtypes.Log, error)
 
 // revision is the identifier of a version of state.
@@ -43,7 +44,7 @@ type revision struct {
 	journalIndex int
 }
 
-var _ vm.StateDB = &StateDB{}
+var _ vm.StateDB = (*StateDB)(nil)
 
 // StateDB structs within the ethereum protocol are used to store anything
 // within the merkle trie. StateDBs take care of caching and storing
@@ -85,7 +86,7 @@ type StateDB struct {
 	//nolint
 	evmDenom string
 	//nolint
-	err      error
+	err error
 }
 
 // New creates a new state from a given trie.