consensus/clique: use slices package for sorting (ethereum#27488)

Also adds Address.Less for sorting use in other packages.

---------

Co-authored-by: Felix Lange <fjl@twurst.com>

common/types.go

@@ -226,6 +226,11 @@ func IsHexAddress(s string) bool {
 	return len(s) == 2*AddressLength && isHex(s)
 }
 
+// Less compares two addresses.
+func (a Address) Less(other Address) bool {
+	return bytes.Compare(a[:], other[:]) < 0
+}
+
 // Bytes gets the string representation of the underlying address.
 func (a Address) Bytes() []byte { return a[:] }
 

consensus/clique/snapshot.go

@@ -19,7 +19,6 @@ package clique
 import (
 	"bytes"
 	"encoding/json"
-	"sort"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -29,6 +28,7 @@ import (
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
+	"golang.org/x/exp/slices"
 )
 
 // Vote represents a single vote that an authorized signer made to modify the
@@ -62,13 +62,6 @@ type Snapshot struct {
 	Tally   map[common.Address]Tally    `json:"tally"`   // Current vote tally to avoid recalculating
 }
 
-// signersAscending implements the sort interface to allow sorting a list of addresses
-type signersAscending []common.Address
-
-func (s signersAscending) Len() int           { return len(s) }
-func (s signersAscending) Less(i, j int) bool { return bytes.Compare(s[i][:], s[j][:]) < 0 }
-func (s signersAscending) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
-
 // newSnapshot creates a new snapshot with the specified startup parameters. This
 // method does not initialize the set of recent signers, so only ever use if for
 // the genesis block.
@@ -315,7 +308,7 @@ func (s *Snapshot) signers() []common.Address {
 	for sig := range s.Signers {
 		sigs = append(sigs, sig)
 	}
-	sort.Sort(signersAscending(sigs))
+	slices.SortFunc(sigs, common.Address.Less)
 	return sigs
 }
 

consensus/clique/snapshot_test.go

@@ -21,7 +21,6 @@ import (
 	"crypto/ecdsa"
 	"fmt"
 	"math/big"
-	"sort"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -31,6 +30,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/params"
+	"golang.org/x/exp/slices"
 )
 
 // testerAccountPool is a pool to maintain currently active tester accounts,
@@ -53,7 +53,7 @@ func (ap *testerAccountPool) checkpoint(header *types.Header, signers []string)
 	for i, signer := range signers {
 		auths[i] = ap.address(signer)
 	}
-	sort.Sort(signersAscending(auths))
+	slices.SortFunc(auths, common.Address.Less)
 	for i, auth := range auths {
 		copy(header.Extra[extraVanity+i*common.AddressLength:], auth.Bytes())
 	}