all: replace manual map copying with maps.Copy for improved readability

cmd/devp2p/crawl.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p/enode"
+	"maps"
 )
 
 type crawler struct {
@@ -72,9 +73,7 @@ func newCrawler(input nodeSet, bootnodes []*enode.Node, disc resolver, iters ...
 	c.iters = append(c.iters, c.inputIter)
 	// Copy input to output initially. Any nodes that fail validation
 	// will be dropped from output during the run.
-	for id, n := range input {
+	maps.Copy(c.output, input)
-		c.output[id] = n
-	}
 	return c, nil
 }
 

consensus/clique/api.go

@@ -26,6 +26,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/rpc"
+	"maps"
 )
 
 // API is a user facing RPC API to allow controlling the signer and voting
@@ -99,9 +100,7 @@ func (api *API) Proposals() map[common.Address]bool {
 	defer api.clique.lock.RUnlock()
 
 	proposals := make(map[common.Address]bool)
-	for address, auth := range api.clique.proposals {
+	maps.Copy(proposals, api.clique.proposals)
-		proposals[address] = auth
-	}
 	return proposals
 }
 

core/blockchain_test.go

@@ -45,6 +45,7 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/trie"
 	"github.com/holiman/uint256"
+	"maps"
 )
 
 // So we can deterministically seed different blockchains
@@ -3062,9 +3063,7 @@ func testDeleteRecreateSlotsAcrossManyBlocks(t *testing.T, scheme string) {
 		var exp = new(expectation)
 		exp.blocknum = i + 1
 		exp.values = make(map[int]int)
-		for k, v := range current.values {
+		maps.Copy(exp.values, current.values)
-			exp.values[k] = v
-		}
 		exp.exist = current.exist
 
 		b.SetCoinbase(common.Address{1})

core/state/snapshot/difflayer.go

@@ -388,9 +388,7 @@ func (dl *diffLayer) flatten() snapshot {
 	if parent.stale.Swap(true) {
 		panic("parent diff layer is stale") // we've flattened into the same parent from two children, boo
 	}
-	for hash, data := range dl.accountData {
+	maps.Copy(parent.accountData, dl.accountData)
-		parent.accountData[hash] = data
-	}
 	// Overwrite all the updated storage slots (individually)
 	for accountHash, storage := range dl.storageData {
 		// If storage didn't exist (or was deleted) in the parent, overwrite blindly

core/state/snapshot/difflayer_test.go

@@ -26,13 +26,12 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/ethdb/memorydb"
+	"maps"
 )
 
 func copyAccounts(accounts map[common.Hash][]byte) map[common.Hash][]byte {
 	copy := make(map[common.Hash][]byte)
-	for hash, blob := range accounts {
+	maps.Copy(copy, accounts)
-		copy[hash] = blob
-	}
 	return copy
 }
 
@@ -40,9 +39,7 @@ func copyStorage(storage map[common.Hash]map[common.Hash][]byte) map[common.Hash
 	copy := make(map[common.Hash]map[common.Hash][]byte)
 	for accHash, slots := range storage {
 		copy[accHash] = make(map[common.Hash][]byte)
-		for slotHash, blob := range slots {
+		maps.Copy(copy[accHash], slots)
-			copy[accHash][slotHash] = blob
-		}
 	}
 	return copy
 }

core/txpool/txpool.go

@@ -29,6 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/metrics"
+	"maps"
 )
 
 // TxStatus is the current status of a transaction as seen by the pool.
@@ -390,9 +391,7 @@ func (p *TxPool) Add(txs []*types.Transaction, sync bool) []error {
 func (p *TxPool) Pending(filter PendingFilter) map[common.Address][]*LazyTransaction {
 	txs := make(map[common.Address][]*LazyTransaction)
 	for _, subpool := range p.subpools {
-		for addr, set := range subpool.Pending(filter) {
+		maps.Copy(txs, subpool.Pending(filter))
-			txs[addr] = set
-		}
 	}
 	return txs
 }
@@ -445,12 +444,8 @@ func (p *TxPool) Content() (map[common.Address][]*types.Transaction, map[common.
 	for _, subpool := range p.subpools {
 		run, block := subpool.Content()
 
-		for addr, txs := range run {
+		maps.Copy(runnable, run)
-			runnable[addr] = txs
+		maps.Copy(blocked, block)
-		}
-		for addr, txs := range block {
-			blocked[addr] = txs
-		}
 	}
 	return runnable, blocked
 }

rpc/client_opt.go

@@ -20,6 +20,7 @@ import (
 	"net/http"
 
 	"github.com/gorilla/websocket"
+	"maps"
 )
 
 // ClientOption is a configuration option for the RPC client.
@@ -89,9 +90,7 @@ func WithHeader(key, value string) ClientOption {
 func WithHeaders(headers http.Header) ClientOption {
 	return optionFunc(func(cfg *clientConfig) {
 		cfg.initHeaders()
-		for k, vs := range headers {
+		maps.Copy(cfg.httpHeaders, headers)
-			cfg.httpHeaders[k] = vs
-		}
 	})
 }
 

rpc/http.go

@@ -23,6 +23,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"math"
 	"mime"
 	"net/http"
@@ -146,9 +147,7 @@ func newClientTransportHTTP(endpoint string, cfg *clientConfig) reconnectFunc {
 	headers := make(http.Header, 2+len(cfg.httpHeaders))
 	headers.Set("accept", contentType)
 	headers.Set("content-type", contentType)
-	for key, values := range cfg.httpHeaders {
+	maps.Copy(headers, cfg.httpHeaders)
-		headers[key] = values
-	}
 
 	client := cfg.httpClient
 	if client == nil {

rpc/websocket.go

@@ -30,6 +30,7 @@ import (
 	mapset "github.com/deckarep/golang-set/v2"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/gorilla/websocket"
+	"maps"
 )
 
 const (
@@ -236,9 +237,7 @@ func newClientTransportWS(endpoint string, cfg *clientConfig) (reconnectFunc, er
 	if err != nil {
 		return nil, err
 	}
-	for key, values := range cfg.httpHeaders {
+	maps.Copy(header, cfg.httpHeaders)
-		header[key] = values
-	}
 
 	connect := func(ctx context.Context) (ServerCodec, error) {
 		header := header.Clone()