feat: CheckConfig{Compatible,ForkOrder} + Description hooks

Author: ARR4N

libevm/hookstest/stub.go

@@ -25,6 +25,9 @@ func Register[C params.ChainConfigHooks, R params.RulesHooks](tb testing.TB, ext
 // [params.RulesHooks]. Each of the fields, if non-nil, back their respective
 // hook methods, which otherwise fall back to the default behaviour.
 type Stub struct {
+	CheckConfigForkOrderFn  func() error
+	CheckConfigCompatibleFn func(*params.ChainConfig, *big.Int, uint64) *params.ConfigCompatError
+	DescriptionValue        string
 	PrecompileOverrides     map[common.Address]libevm.PrecompiledContract
 	CanExecuteTransactionFn func(common.Address, *common.Address, libevm.StateReader) error
 	CanCreateContractFn     func(*libevm.AddressContext, libevm.StateReader) error
@@ -52,6 +55,29 @@ func (s Stub) PrecompileOverride(a common.Address) (libevm.PrecompiledContract,
 	return p, ok
 }
 
+// CheckConfigForkOrder proxies arguments to the s.CheckConfigForkOrderFn
+// function if non-nil, otherwise it acts as a noop.
+func (s Stub) CheckConfigForkOrder() error {
+	if f := s.CheckConfigForkOrderFn; f != nil {
+		return f()
+	}
+	return nil
+}
+
+// CheckConfigCompatible proxies arguments to the s.CheckConfigCompatibleFn
+// function if non-nil, otherwise it acts as a noop.
+func (s Stub) CheckConfigCompatible(newcfg *params.ChainConfig, headNumber *big.Int, headTimestamp uint64) *params.ConfigCompatError {
+	if f := s.CheckConfigCompatibleFn; f != nil {
+		return f(newcfg, headNumber, headTimestamp)
+	}
+	return nil
+}
+
+// Description returns s.DescriptionValue.
+func (s Stub) Description() string {
+	return s.DescriptionValue
+}
+
 // CanExecuteTransaction proxies arguments to the s.CanExecuteTransactionFn
 // function if non-nil, otherwise it acts as a noop.
 func (s Stub) CanExecuteTransaction(from common.Address, to *common.Address, sr libevm.StateReader) error {

params/config.go

@@ -478,7 +478,7 @@ func (c *ChainConfig) Description() string {
 	if c.VerkleTime != nil {
 		banner += fmt.Sprintf(" - Verkle:                      @%-10v\n", *c.VerkleTime)
 	}
-	return banner
+	return banner + c.Hooks().Description()
 }
 
 // IsHomestead returns whether num is either equal to the homestead block or greater.
@@ -671,7 +671,7 @@ func (c *ChainConfig) CheckConfigForkOrder() error {
 			lastFork = cur
 		}
 	}
-	return nil
+	return c.Hooks().CheckConfigForkOrder()
 }
 
 func (c *ChainConfig) checkCompatible(newcfg *ChainConfig, headNumber *big.Int, headTimestamp uint64) *ConfigCompatError {
@@ -742,7 +742,7 @@ func (c *ChainConfig) checkCompatible(newcfg *ChainConfig, headNumber *big.Int,
 	if isForkTimestampIncompatible(c.VerkleTime, newcfg.VerkleTime, headTimestamp) {
 		return newTimestampCompatError("Verkle fork timestamp", c.VerkleTime, newcfg.VerkleTime)
 	}
-	return nil
+	return c.Hooks().CheckConfigCompatible(newcfg, headNumber, headTimestamp)
 }
 
 // BaseFeeChangeDenominator bounds the amount the base fee can change between blocks.

params/example.libevm_test.go

@@ -51,6 +51,11 @@ func constructRulesExtra(c *params.ChainConfig, r *params.Rules, cEx ChainConfig
 // the standard [params.ChainConfig] struct.
 type ChainConfigExtra struct {
 	MyForkTime *uint64 `json:"myForkTime"`
+
+	// (Optional) If not all hooks are desirable then embedding a [NOOPHooks]
+	// allows the type to satisfy the [ChainConfigHooks] interface, resulting in
+	// default Ethereum behaviour.
+	params.NOOPHooks
 }
 
 // RulesExtra can be any struct. It too mirrors a common pattern in
@@ -59,9 +64,6 @@ type RulesExtra struct {
 	IsMyFork  bool
 	timestamp uint64
 
-	// (Optional) If not all hooks are desirable then embedding a [NOOPHooks]
-	// allows the type to satisfy the [RulesHooks] interface, resulting in
-	// default Ethereum behaviour.
 	params.NOOPHooks
 }
 

params/hooks.libevm.go

@@ -1,13 +1,19 @@
 package params
 
 import (
+	"math/big"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/libevm"
 )
 
 // ChainConfigHooks are required for all types registered as [Extras] for
 // [ChainConfig] payloads.
-type ChainConfigHooks interface{}
+type ChainConfigHooks interface {
+	CheckConfigForkOrder() error
+	CheckConfigCompatible(newcfg *ChainConfig, headNumber *big.Int, headTimestamp uint64) *ConfigCompatError
+	Description() string
+}
 
 // TODO(arr4n): given the choice of whether a hook should be defined on a
 // ChainConfig or on the Rules, what are the guiding principles? A ChainConfig
@@ -66,6 +72,18 @@ var _ interface {
 	RulesHooks
 } = NOOPHooks{}
 
+func (NOOPHooks) CheckConfigForkOrder() error {
+	return nil
+}
+
+func (NOOPHooks) CheckConfigCompatible(*ChainConfig, *big.Int, uint64) *ConfigCompatError {
+	return nil
+}
+
+func (NOOPHooks) Description() string {
+	return ""
+}
+
 // CanExecuteTransaction allows all (otherwise valid) transactions.
 func (NOOPHooks) CanExecuteTransaction(_ common.Address, _ *common.Address, _ libevm.StateReader) error {
 	return nil