From b9a2722ff085cb9b391cc88c650eff31e233a37e Mon Sep 17 00:00:00 2001
From: Elad Nachmias <theman@elad.im>
Date: Wed, 20 Feb 2019 17:03:35 +0700
Subject: [PATCH] contracts/ens: added test coverage for fallback contract

---
 contracts/ens/ens.go                          | 37 ++++++++++++++++++-
 contracts/ens/ens_test.go                     | 27 ++++++++++++++
 contracts/ens/fallback_contract/ens.go        |  2 +-
 .../ens/fallback_contract/fifsregistrar.go    |  2 +-
 .../ens/fallback_contract/publicresolver.go   |  2 +-
 5 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/contracts/ens/ens.go b/contracts/ens/ens.go
index 776c622f44..3482ec071f 100644
--- a/contracts/ens/ens.go
+++ b/contracts/ens/ens.go
@@ -22,6 +22,7 @@ package ens
 //go:generate abigen --sol contract/PublicResolver.sol --exc contract/ENS.sol:ENS --pkg contract --out contract/publicresolver.go
 
 import (
+	"encoding/binary"
 	"strings"
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
@@ -32,10 +33,17 @@ import (
 )
 
 var (
-	MainNetAddress = common.HexToAddress("0x314159265dD8dbb310642f98f50C066173C1259b")
-	TestNetAddress = common.HexToAddress("0x112234455c3a32fd11230c42e7bccd4a84e02010")
+	MainNetAddress           = common.HexToAddress("0x314159265dD8dbb310642f98f50C066173C1259b")
+	TestNetAddress           = common.HexToAddress("0x112234455c3a32fd11230c42e7bccd4a84e02010")
+	contentHash_Interface_Id [4]byte
 )
 
+const contentHash_Interface_Id_Spec = 0xbc1c58d1
+
+func init() {
+	binary.BigEndian.PutUint32(contentHash_Interface_Id[:], contentHash_Interface_Id_Spec)
+}
+
 // ENS is the swarm domain name registry and resolver
 type ENS struct {
 	*contract.ENSSession
@@ -135,6 +143,18 @@ func (ens *ENS) Resolve(name string) (common.Hash, error) {
 		return common.Hash{}, err
 	}
 
+	// IMPORTANT: The old contract is deprecated. This code should be removed latest on June 1st 2019
+	supported, err := resolver.SupportsInterface(contentHash_Interface_Id)
+	if err != nil {
+		return common.Hash{}, err
+	}
+
+	if !supported {
+		panic("w00t")
+	}
+
+	// END DEPRECATED CODE
+
 	ret, err := resolver.Contenthash(node)
 	if err != nil {
 		return common.Hash{}, err
@@ -191,6 +211,19 @@ func (ens *ENS) SetContentHash(name string, hash []byte) (*types.Transaction, er
 	if err != nil {
 		return nil, err
 	}
+
+	// IMPORTANT: The old contract is deprecated. This code should be removed latest on June 1st 2019
+	supported, err := resolver.SupportsInterface(contentHash_Interface_Id)
+	if err != nil {
+		return nil, err
+	}
+
+	if !supported {
+		panic("w00t")
+	}
+
+	// END DEPRECATED CODE
+
 	opts := ens.TransactOpts
 	opts.GasLimit = 200000
 	return resolver.Contract.SetContenthash(&opts, node, hash)
diff --git a/contracts/ens/ens_test.go b/contracts/ens/ens_test.go
index 862d462580..21b05427d4 100644
--- a/contracts/ens/ens_test.go
+++ b/contracts/ens/ens_test.go
@@ -24,6 +24,7 @@ import (
 	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/contracts/ens/contract"
+	"github.com/ethereum/go-ethereum/contracts/ens/fallback_contract"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/crypto"
 )
@@ -91,4 +92,30 @@ func TestENS(t *testing.T) {
 	if testAddr != recoveredAddr {
 		t.Fatalf("resolve error, expected %v, got %v", testAddr.Hex(), recoveredAddr.Hex())
 	}
+
+	// deploy the fallback contract and see that the fallback mechanism works
+	newResolverAddr, _, _, err := fallback_contract.DeployPublicResolver(transactOpts, contractBackend, ensAddr)
+	if err != nil {
+		t.Fatalf("can't deploy resolver: %v", err)
+	}
+	if _, err := ens.SetResolver(EnsNode(name), newResolverAddr); err != nil {
+		t.Fatalf("can't set resolver: %v", err)
+	}
+	contractBackend.Commit()
+
+	// Set the content hash for the name.
+	if _, err = ens.SetContentHash(name, hash.Bytes()); err != nil {
+		t.Fatalf("can't set content hash: %v", err)
+	}
+	contractBackend.Commit()
+
+	// Try to resolve the name.
+	vhost, err = ens.Resolve(name)
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+	if vhost != hash {
+		t.Fatalf("resolve error, expected %v, got %v", hash.Hex(), vhost.Hex())
+	}
+
 }
diff --git a/contracts/ens/fallback_contract/ens.go b/contracts/ens/fallback_contract/ens.go
index 8827071afc..b156584b71 100644
--- a/contracts/ens/fallback_contract/ens.go
+++ b/contracts/ens/fallback_contract/ens.go
@@ -1,7 +1,7 @@
 // Code generated - DO NOT EDIT.
 // This file is a generated binding and any manual changes will be lost.
 
-package contract
+package fallback_contract
 
 import (
 	"strings"
diff --git a/contracts/ens/fallback_contract/fifsregistrar.go b/contracts/ens/fallback_contract/fifsregistrar.go
index a08380adfc..879f737576 100644
--- a/contracts/ens/fallback_contract/fifsregistrar.go
+++ b/contracts/ens/fallback_contract/fifsregistrar.go
@@ -1,7 +1,7 @@
 // Code generated - DO NOT EDIT.
 // This file is a generated binding and any manual changes will be lost.
 
-package contract
+package fallback_contract
 
 import (
 	"strings"
diff --git a/contracts/ens/fallback_contract/publicresolver.go b/contracts/ens/fallback_contract/publicresolver.go
index c567d5884a..a2a4be1c16 100644
--- a/contracts/ens/fallback_contract/publicresolver.go
+++ b/contracts/ens/fallback_contract/publicresolver.go
@@ -1,7 +1,7 @@
 // Code generated - DO NOT EDIT.
 // This file is a generated binding and any manual changes will be lost.
 
-package contract
+package fallback_contract
 
 import (
 	"math/big"