eth, les, params: log chain config a bit saner (ethereum#24904)

Previously on Geth startup we just logged the chain config is a semi-json-y format. Whilst that worked while we had a handful of hard-forks defined, currently it's kind of unwieldy. 

This PR converts that original data dump and converts it into a user friendly - alas multiline - log output.

core/forkid/forkid_test.go

@@ -31,7 +31,7 @@ import (
 // the correct fork ID.
 func TestCreation(t *testing.T) {
 	mergeConfig := *params.MainnetChainConfig
-	mergeConfig.MergeForkBlock = big.NewInt(15000000)
+	mergeConfig.MergeNetsplitBlock = big.NewInt(15000000)
 	type testcase struct {
 		head uint64
 		want ID

eth/backend.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"math/big"
 	"runtime"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -140,7 +141,13 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 	if _, ok := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !ok {
 		return nil, genesisErr
 	}
-	log.Info("Initialised chain configuration", "config", chainConfig)
+	log.Info("")
+	log.Info(strings.Repeat("-", 153))
+	for _, line := range strings.Split(chainConfig.String(), "\n") {
+		log.Info(line)
+	}
+	log.Info(strings.Repeat("-", 153))
+	log.Info("")
 
 	if err := pruner.RecoverPruning(stack.ResolvePath(""), chainDb, stack.ResolvePath(config.TrieCleanCacheJournal)); err != nil {
 		log.Error("Failed to recover state", "error", err)

les/client.go

@@ -19,6 +19,7 @@ package les
 
 import (
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/ethereum/go-ethereum/accounts"
@@ -96,7 +97,13 @@ func New(stack *node.Node, config *ethconfig.Config) (*LightEthereum, error) {
 	if _, isCompat := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !isCompat {
 		return nil, genesisErr
 	}
-	log.Info("Initialised chain configuration", "config", chainConfig)
+	log.Info("")
+	log.Info(strings.Repeat("-", 153))
+	for _, line := range strings.Split(chainConfig.String(), "\n") {
+		log.Info(line)
+	}
+	log.Info(strings.Repeat("-", 153))
+	log.Info("")
 
 	peers := newServerPeerSet()
 	merger := consensus.NewMerger(chainDb)

params/config.go

@@ -272,6 +272,15 @@ var (
 	TestRules       = TestChainConfig.Rules(new(big.Int), false)
 )
 
+// NetworkNames are user friendly names to use in the chain spec banner.
+var NetworkNames = map[string]string{
+	MainnetChainConfig.ChainID.String(): "mainnet",
+	RopstenChainConfig.ChainID.String(): "ropsten",
+	RinkebyChainConfig.ChainID.String(): "rinkeby",
+	GoerliChainConfig.ChainID.String():  "goerli",
+	SepoliaChainConfig.ChainID.String(): "sepolia",
+}
+
 // TrustedCheckpoint represents a set of post-processed trie roots (CHT and
 // BloomTrie) associated with the appropriate section index and head hash. It is
 // used to start light syncing from this checkpoint and avoid downloading the
@@ -348,7 +357,7 @@ type ChainConfig struct {
 	BerlinBlock         *big.Int `json:"berlinBlock,omitempty"`         // Berlin switch block (nil = no fork, 0 = already on berlin)
 	LondonBlock         *big.Int `json:"londonBlock,omitempty"`         // London switch block (nil = no fork, 0 = already on london)
 	ArrowGlacierBlock   *big.Int `json:"arrowGlacierBlock,omitempty"`   // Eip-4345 (bomb delay) switch block (nil = no fork, 0 = already activated)
-	MergeForkBlock      *big.Int `json:"mergeForkBlock,omitempty"`      // EIP-3675 (TheMerge) switch block (nil = no fork, 0 = already in merge proceedings)
+	MergeNetsplitBlock  *big.Int `json:"mergeNetsplitBlock,omitempty"`  // Virtual fork after The Merge to use as a network splitter
 
 	// TerminalTotalDifficulty is the amount of total difficulty reached by
 	// the network that triggers the consensus upgrade.
@@ -380,35 +389,68 @@ func (c *CliqueConfig) String() string {
 
 // String implements the fmt.Stringer interface.
 func (c *ChainConfig) String() string {
-	var engine interface{}
+	var banner string
+
+	// Create some basinc network config output
+	network := NetworkNames[c.ChainID.String()]
+	if network == "" {
+		network = "unknown"
+	}
+	banner += fmt.Sprintf("Chain ID:  %v (%s)\n", c.ChainID, network)
 	switch {
 	case c.Ethash != nil:
-		engine = c.Ethash
+		if c.TerminalTotalDifficulty == nil {
+			banner += "Consensus: Ethash (proof-of-work)\n"
+		} else {
+			banner += "Consensus: Beacon (proof-of-stake), merged from Ethash (proof-of-work)\n"
+		}
 	case c.Clique != nil:
-		engine = c.Clique
+		if c.TerminalTotalDifficulty == nil {
+			banner += "Consensus: Clique (proof-of-authority)\n"
+		} else {
+			banner += "Consensus: Beacon (proof-of-stake), merged from Clique (proof-of-authority)\n"
+		}
 	default:
-		engine = "unknown"
-	}
-	return fmt.Sprintf("{ChainID: %v Homestead: %v DAO: %v DAOSupport: %v EIP150: %v EIP155: %v EIP158: %v Byzantium: %v Constantinople: %v Petersburg: %v Istanbul: %v, Muir Glacier: %v, Berlin: %v, London: %v, Arrow Glacier: %v, MergeFork: %v, Terminal TD: %v, Engine: %v}",
-		c.ChainID,
-		c.HomesteadBlock,
-		c.DAOForkBlock,
-		c.DAOForkSupport,
-		c.EIP150Block,
-		c.EIP155Block,
-		c.EIP158Block,
-		c.ByzantiumBlock,
-		c.ConstantinopleBlock,
-		c.PetersburgBlock,
-		c.IstanbulBlock,
-		c.MuirGlacierBlock,
-		c.BerlinBlock,
-		c.LondonBlock,
-		c.ArrowGlacierBlock,
-		c.MergeForkBlock,
-		c.TerminalTotalDifficulty,
-		engine,
-	)
+		banner += "Consensus: unknown\n"
+	}
+	banner += "\n"
+
+	// Create a list of forks with a short description of them. Forks that only
+	// makes sense for mainnet should be optional at printing to avoid bloating
+	// the output for testnets and private networks.
+	banner += "Pre-Merge hard forks:\n"
+	banner += fmt.Sprintf(" - Homestead:                   %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/homestead.md)\n", c.HomesteadBlock)
+	if c.DAOForkBlock != nil {
+		banner += fmt.Sprintf(" - DAO Fork:                    %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/dao-fork.md)\n", c.DAOForkBlock)
+	}
+	banner += fmt.Sprintf(" - Tangerine Whistle (EIP 150): %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/tangerine-whistle.md)\n", c.EIP150Block)
+	banner += fmt.Sprintf(" - Spurious Dragon/1 (EIP 155): %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/spurious-dragon.md)\n", c.EIP155Block)
+	banner += fmt.Sprintf(" - Spurious Dragon/2 (EIP 158): %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/spurious-dragon.md)\n", c.EIP155Block)
+	banner += fmt.Sprintf(" - Byzantium:                   %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/byzantium.md)\n", c.ByzantiumBlock)
+	banner += fmt.Sprintf(" - Constantinople:              %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/constantinople.md)\n", c.ConstantinopleBlock)
+	banner += fmt.Sprintf(" - Petersburg:                  %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/petersburg.md)\n", c.PetersburgBlock)
+	banner += fmt.Sprintf(" - Istanbul:                    %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/istanbul.md)\n", c.IstanbulBlock)
+	if c.MuirGlacierBlock != nil {
+		banner += fmt.Sprintf(" - Muir Glacier:                %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/muir-glacier.md)\n", c.MuirGlacierBlock)
+	}
+	banner += fmt.Sprintf(" - Berlin:                      %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/berlin.md)\n", c.BerlinBlock)
+	banner += fmt.Sprintf(" - London:                      %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/london.md)\n", c.LondonBlock)
+	if c.ArrowGlacierBlock != nil {
+		banner += fmt.Sprintf(" - Arrow Glacier:               %-8v (https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/arrow-glacier.md)\n", c.ArrowGlacierBlock)
+	}
+	banner += "\n"
+
+	// Add a special section for the merge as it's non-obvious
+	if c.TerminalTotalDifficulty == nil {
+		banner += "Merge not configured!\n"
+		banner += " - Hard-fork specification: https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/paris.md)"
+	} else {
+		banner += "Merge configured:\n"
+		banner += " - Hard-fork specification:   https://github.com/ethereum/execution-specs/blob/master/network-upgrades/mainnet-upgrades/paris.md)\n"
+		banner += fmt.Sprintf(" - Total terminal difficulty: %v\n", c.TerminalTotalDifficulty)
+		banner += fmt.Sprintf(" - Merge netsplit block:      %-8v", c.MergeNetsplitBlock)
+	}
+	return banner
 }
 
 // IsHomestead returns whether num is either equal to the homestead block or greater.
@@ -527,7 +569,7 @@ func (c *ChainConfig) CheckConfigForkOrder() error {
 		{name: "berlinBlock", block: c.BerlinBlock},
 		{name: "londonBlock", block: c.LondonBlock},
 		{name: "arrowGlacierBlock", block: c.ArrowGlacierBlock, optional: true},
-		{name: "mergeStartBlock", block: c.MergeForkBlock, optional: true},
+		{name: "mergeNetsplitBlock", block: c.MergeNetsplitBlock, optional: true},
 	} {
 		if lastFork.name != "" {
 			// Next one must be higher number
@@ -600,8 +642,8 @@ func (c *ChainConfig) checkCompatible(newcfg *ChainConfig, head *big.Int) *Confi
 	if isForkIncompatible(c.ArrowGlacierBlock, newcfg.ArrowGlacierBlock, head) {
 		return newCompatError("Arrow Glacier fork block", c.ArrowGlacierBlock, newcfg.ArrowGlacierBlock)
 	}
-	if isForkIncompatible(c.MergeForkBlock, newcfg.MergeForkBlock, head) {
-		return newCompatError("Merge Start fork block", c.MergeForkBlock, newcfg.MergeForkBlock)
+	if isForkIncompatible(c.MergeNetsplitBlock, newcfg.MergeNetsplitBlock, head) {
+		return newCompatError("Merge netsplit fork block", c.MergeNetsplitBlock, newcfg.MergeNetsplitBlock)
 	}
 	return nil
 }

tests/init.go

@@ -211,7 +211,7 @@ var Forks = map[string]*params.ChainConfig{
 		BerlinBlock:             big.NewInt(0),
 		LondonBlock:             big.NewInt(0),
 		ArrowGlacierBlock:       big.NewInt(0),
-		MergeForkBlock:          big.NewInt(0),
+		MergeNetsplitBlock:      big.NewInt(0),
 		TerminalTotalDifficulty: big.NewInt(0),
 	},
 }