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

This reverts commit cd00ee32ba.

common/types.go

@@ -226,11 +226,6 @@ 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

@@ -19,6 +19,7 @@ package clique
 import (
 	"bytes"
 	"encoding/json"
+	"sort"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -28,7 +29,6 @@ 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
@@ -62,6 +62,13 @@ 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.
@@ -308,7 +315,7 @@ func (s *Snapshot) signers() []common.Address {
 	for sig := range s.Signers {
 		sigs = append(sigs, sig)
 	}
-	slices.SortFunc(sigs, common.Address.Less)
+	sort.Sort(signersAscending(sigs))
 	return sigs
 }
 

consensus/clique/snapshot_test.go

@@ -21,6 +21,7 @@ import (
 	"crypto/ecdsa"
 	"fmt"
 	"math/big"
+	"sort"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -30,7 +31,6 @@ 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)
 	}
-	slices.SortFunc(auths, common.Address.Less)
+	sort.Sort(signersAscending(auths))
 	for i, auth := range auths {
 		copy(header.Extra[extraVanity+i*common.AddressLength:], auth.Bytes())
 	}