add events to helloworld

contracts/contracts/interfaces/IHelloWorld.sol

@@ -7,6 +7,7 @@ pragma solidity >=0.8.0;
 import "./IAllowList.sol";
 
 interface IHelloWorld is IAllowList {
+  event GreetingChanged(address indexed sender, string oldGreeting, string newGreeting);
   // sayHello returns the stored greeting string
   function sayHello() external view returns (string calldata result);
 

contracts/test/hello_world.ts

@@ -1,6 +1,9 @@
 // (c) 2019-2022, Ava Labs, Inc. All rights reserved.
 // See the file LICENSE for licensing terms.
 
+import { expect } from "chai"
+import { SignerWithAddress } from "@nomiclabs/hardhat-ethers/signers";
+import { Contract } from "ethers"
 import { ethers } from "hardhat"
 import { test } from "./utils"
 
@@ -32,3 +35,29 @@ describe("ExampleHelloWorldTest", function () {
 
   test("should set and get greeting with enabled account", "step_setAndGetGreeting")
 });
+
+describe("IHelloWorld events", function () {
+  let owner: SignerWithAddress
+  let contract: Contract
+  let defaultGreeting = "Hello, World!"
+  before(async function () {
+    owner = await ethers.getSigner(ADMIN_ADDRESS);
+    contract = await ethers.getContractAt("IHelloWorld", HELLO_WORLD_ADDRESS, owner)
+
+    // reset greeting
+    let tx = await contract.setGreeting(defaultGreeting)
+    await tx.wait()
+  });
+
+  it("should emit GreetingChanged event", async function () {
+    let newGreeting = "helloprecompile"
+    await expect(contract.setGreeting(newGreeting)
+    )
+    .to.emit(contract, "GreetingChanged").withArgs(owner.address,
+      // old greeting
+      defaultGreeting,
+      // new greeting
+      newGreeting
+    )
+  })
+})

precompile/contracts/helloworld/config.go

@@ -5,8 +5,6 @@
 package helloworld
 
 import (
-	"math/big"
-
 	"github.com/ava-labs/subnet-evm/precompile/allowlist"
 	"github.com/ava-labs/subnet-evm/precompile/precompileconfig"
 
@@ -25,20 +23,21 @@ type Config struct {
 }
 
 // NewConfig returns a config for a network upgrade at [blockTimestamp] that enables
-// HelloWorld with the given [admins] as members of the allowlist .
-func NewConfig(blockTimestamp *big.Int, admins []common.Address, enableds []common.Address) *Config {
+// HelloWorld with the given [admins], [enableds] and [managers] members of the allowlist .
+func NewConfig(blockTimestamp *uint64, admins []common.Address, enableds []common.Address, managers []common.Address) *Config {
 	return &Config{
 		AllowListConfig: allowlist.AllowListConfig{
 			AdminAddresses:   admins,
 			EnabledAddresses: enableds,
+			ManagerAddresses: managers,
 		},
 		Upgrade: precompileconfig.Upgrade{BlockTimestamp: blockTimestamp},
 	}
 }
 
 // NewDisableConfig returns config for a network upgrade at [blockTimestamp]
 // that disables HelloWorld.
-func NewDisableConfig(blockTimestamp *big.Int) *Config {
+func NewDisableConfig(blockTimestamp *uint64) *Config {
 	return &Config{
 		Upgrade: precompileconfig.Upgrade{
 			BlockTimestamp: blockTimestamp,
@@ -52,9 +51,9 @@ func NewDisableConfig(blockTimestamp *big.Int) *Config {
 func (*Config) Key() string { return ConfigKey }
 
 // Verify tries to verify Config and returns an error accordingly.
-func (c *Config) Verify() error {
+func (c *Config) Verify(chainConfig precompileconfig.ChainConfig) error {
 	// Verify AllowList first
-	if err := c.AllowListConfig.Verify(); err != nil {
+	if err := c.AllowListConfig.Verify(chainConfig, c.Upgrade); err != nil {
 		return err
 	}
 	// CUSTOM CODE STARTS HERE

precompile/contracts/helloworld/config_test.go

@@ -1,40 +1,44 @@
-// (c) 2019-2023, Ava Labs, Inc. All rights reserved.
-// See the file LICENSE for licensing terms.
-
 // Code generated
 // This file is a generated precompile config test with the skeleton of test functions.
 // The file is generated by a template. Please inspect every code and comment in this file before use.
 
 package helloworld
 
 import (
-	"math/big"
 	"testing"
 
 	"github.com/ava-labs/subnet-evm/precompile/allowlist"
 	"github.com/ava-labs/subnet-evm/precompile/precompileconfig"
 	"github.com/ava-labs/subnet-evm/precompile/testutils"
+	"github.com/ava-labs/subnet-evm/utils"
 
 	"github.com/ethereum/go-ethereum/common"
+	"go.uber.org/mock/gomock"
 )
 
 // TestVerify tests the verification of Config.
 func TestVerify(t *testing.T) {
 	admins := []common.Address{allowlist.TestAdminAddr}
 	enableds := []common.Address{allowlist.TestEnabledAddr}
+	managers := []common.Address{allowlist.TestManagerAddr}
 	tests := map[string]testutils.ConfigVerifyTest{
 		"valid config": {
-			Config:        NewConfig(big.NewInt(3), admins, enableds),
+			Config: NewConfig(utils.NewUint64(3), admins, enableds, managers),
+			ChainConfig: func() precompileconfig.ChainConfig {
+				config := precompileconfig.NewMockChainConfig(gomock.NewController(t))
+				config.EXPECT().IsDurango(gomock.Any()).Return(true).AnyTimes()
+				return config
+			}(),
 			ExpectedError: "",
 		},
 		// CUSTOM CODE STARTS HERE
 		// Add your own Verify tests here, e.g.:
 		// "your custom test name": {
-		// 	Config: NewConfig(big.NewInt(3), admins, enableds),
+		// 	Config: NewConfig(utils.NewUint64(3), admins, enableds, managers),
 		// 	ExpectedError: ErrYourCustomError.Error(),
 		// },
 		"invalid allow list config in hello world allowlist": {
-			Config:        NewConfig(big.NewInt(3), admins, admins),
+			Config:        NewConfig(utils.NewUint64(3), admins, admins, nil),
 			ExpectedError: "cannot set address",
 		},
 	}
@@ -50,25 +54,26 @@ func TestVerify(t *testing.T) {
 func TestEqual(t *testing.T) {
 	admins := []common.Address{allowlist.TestAdminAddr}
 	enableds := []common.Address{allowlist.TestEnabledAddr}
+	managers := []common.Address{allowlist.TestManagerAddr}
 	tests := map[string]testutils.ConfigEqualTest{
 		"non-nil config and nil other": {
-			Config:   NewConfig(big.NewInt(3), admins, enableds),
+			Config:   NewConfig(utils.NewUint64(3), admins, enableds, managers),
 			Other:    nil,
 			Expected: false,
 		},
 		"different type": {
-			Config:   NewConfig(big.NewInt(3), admins, enableds),
-			Other:    precompileconfig.NewNoopStatefulPrecompileConfig(),
+			Config:   NewConfig(utils.NewUint64(3), admins, enableds, managers),
+			Other:    precompileconfig.NewMockConfig(gomock.NewController(t)),
 			Expected: false,
 		},
 		"different timestamp": {
-			Config:   NewConfig(big.NewInt(3), admins, enableds),
-			Other:    NewConfig(big.NewInt(4), admins, enableds),
+			Config:   NewConfig(utils.NewUint64(3), admins, enableds, managers),
+			Other:    NewConfig(utils.NewUint64(4), admins, enableds, managers),
 			Expected: false,
 		},
 		"same config": {
-			Config:   NewConfig(big.NewInt(3), admins, enableds),
-			Other:    NewConfig(big.NewInt(3), admins, enableds),
+			Config:   NewConfig(utils.NewUint64(3), admins, enableds, managers),
+			Other:    NewConfig(utils.NewUint64(3), admins, enableds, managers),
 			Expected: true,
 		},
 		// CUSTOM CODE STARTS HERE

precompile/contracts/helloworld/contract.abi

@@ -1 +1 @@
-[{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"readAllowList","outputs":[{"internalType":"uint256","name":"role","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"sayHello","outputs":[{"internalType":"string","name":"result","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"setAdmin","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"setEnabled","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"string","name":"response","type":"string"}],"name":"setGreeting","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"setNone","outputs":[],"stateMutability":"nonpayable","type":"function"}]
+[{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"sender","type":"address"},{"indexed":false,"internalType":"string","name":"oldGreeting","type":"string"},{"indexed":false,"internalType":"string","name":"newGreeting","type":"string"}],"name":"GreetingChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"uint256","name":"role","type":"uint256"},{"indexed":true,"internalType":"address","name":"account","type":"address"},{"indexed":true,"internalType":"address","name":"sender","type":"address"},{"indexed":false,"internalType":"uint256","name":"oldRole","type":"uint256"}],"name":"RoleSet","type":"event"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"readAllowList","outputs":[{"internalType":"uint256","name":"role","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"sayHello","outputs":[{"internalType":"string","name":"result","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"setAdmin","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"setEnabled","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"string","name":"response","type":"string"}],"name":"setGreeting","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"setManager","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"addr","type":"address"}],"name":"setNone","outputs":[],"stateMutability":"nonpayable","type":"function"}]

precompile/contracts/helloworld/contract.go

@@ -72,6 +72,17 @@ func PackSayHelloOutput(result string) ([]byte, error) {
 	return HelloWorldABI.PackOutput("sayHello", result)
 }
 
+// UnpackSayHelloOutput attempts to unpack given [output] into the string type output
+// assumes that [output] does not include selector (omits first 4 func signature bytes)
+func UnpackSayHelloOutput(output []byte) (string, error) {
+	res, err := HelloWorldABI.Unpack("sayHello", output)
+	if err != nil {
+		return "", err
+	}
+	unpacked := *abi.ConvertType(res[0], new(string)).(*string)
+	return unpacked, nil
+}
+
 // GetGreeting returns the value of the storage key "storageKey" in the contract storage,
 // with leading zeroes trimmed.
 // This function is mostly used for tests.
@@ -105,8 +116,16 @@ func sayHello(accessibleState contract.AccessibleState, caller common.Address, a
 
 // UnpackSetGreetingInput attempts to unpack [input] into the string type argument
 // assumes that [input] does not include selector (omits first 4 func signature bytes)
-func UnpackSetGreetingInput(input []byte) (string, error) {
-	res, err := HelloWorldABI.UnpackInput("setGreeting", input)
+// if [useStrictMode] is true, it will return an error if the length of [input] is not [common.HashLength]
+func UnpackSetGreetingInput(input []byte, useStrictMode bool) (string, error) {
+	// Initially we had this check to ensure that the input was the correct length.
+	// However solidity does not always pack the input to the correct length, and allows
+	// for extra padding bytes to be added to the end of the input. Therefore, we have removed
+	// this check with the Durango. We still need to keep this check for backwards compatibility.
+	if useStrictMode && len(input) > common.HashLength {
+		return "", ErrInputExceedsLimit
+	}
+	res, err := HelloWorldABI.UnpackInput("setGreeting", input, useStrictMode)
 	if err != nil {
 		return "", err
 	}
@@ -137,10 +156,12 @@ func setGreeting(accessibleState contract.AccessibleState, caller common.Address
 	if readOnly {
 		return nil, remainingGas, vmerrs.ErrWriteProtection
 	}
+	// do not use strict mode after Durango
+	useStrictMode := !contract.IsDurangoActivated(accessibleState)
 	// attempts to unpack [input] into the arguments to the SetGreetingInput.
 	// Assumes that [input] does not include selector
 	// You can use unpacked [inputStruct] variable in your code
-	inputStruct, err := UnpackSetGreetingInput(input)
+	inputStruct, err := UnpackSetGreetingInput(input, useStrictMode)
 	if err != nil {
 		return nil, remainingGas, err
 	}
@@ -157,9 +178,40 @@ func setGreeting(accessibleState contract.AccessibleState, caller common.Address
 	// allow list code ends here.
 
 	// CUSTOM CODE STARTS HERE
-	// Check if the input string is longer than HashLength
-	if len(inputStruct) > common.HashLength {
-		return nil, 0, ErrInputExceedsLimit
+	// With Durango, you can emit an event in your state-changing precompile functions.
+	// Note: If you have been using the precompile before Durango, you should activate it only after Durango.
+	// Activating this code before Durango will result in a consensus failure.
+	// If this is a new precompile and never deployed before Durango, you can activate it immediately by removing
+	// the if condition.
+	// This example assumes that the HelloWorld precompile contract has been deployed before Durango.
+	if contract.IsDurangoActivated(accessibleState) {
+		// We will first read the old greeting. So we should charge the gas for reading the storage.
+		if remainingGas, err = contract.DeductGas(remainingGas, contract.ReadGasCostPerSlot); err != nil {
+			return nil, 0, err
+		}
+		oldGreeting := GetGreeting(stateDB)
+
+		eventData := GreetingChangedEventData{
+			OldGreeting: oldGreeting,
+			NewGreeting: inputStruct,
+		}
+		topics, data, err := PackGreetingChangedEvent(caller, eventData)
+		if err != nil {
+			return nil, remainingGas, err
+		}
+		// Charge the gas for emitting the event.
+		eventGasCost := GetGreetingChangedEventGasCost(eventData)
+		if remainingGas, err = contract.DeductGas(remainingGas, eventGasCost); err != nil {
+			return nil, 0, err
+		}
+
+		// Emit the event
+		stateDB.AddLog(
+			ContractAddress,
+			topics,
+			data,
+			accessibleState.GetBlockContext().Number().Uint64(),
+		)
 	}
 
 	// setGreeting is the execution function