feat(core/types): Header hook PostCopy (#106)

core/types/block.go

@@ -309,6 +309,7 @@ func CopyHeader(h *Header) *Header {
 		cpy.ParentBeaconRoot = new(common.Hash)
 		*cpy.ParentBeaconRoot = *h.ParentBeaconRoot
 	}
+	h.hooks().PostCopy(&cpy)
 	return &cpy
 }
 

core/types/block.libevm.go

@@ -32,6 +32,7 @@ type HeaderHooks interface {
 	UnmarshalJSON(*Header, []byte) error //nolint:govet
 	EncodeRLP(*Header, io.Writer) error
 	DecodeRLP(*Header, *rlp.Stream) error
+	PostCopy(dst *Header)
 }
 
 // hooks returns the Header's registered HeaderHooks, if any, otherwise a
@@ -108,3 +109,5 @@ func (*NOOPHeaderHooks) DecodeRLP(h *Header, s *rlp.Stream) error {
 	type withoutMethods Header
 	return s.Decode((*withoutMethods)(h))
 }
+
+func (n *NOOPHeaderHooks) PostCopy(dst *Header) {}

core/types/block.libevm_test.go

@@ -29,6 +29,7 @@ import (
 	. "github.com/ava-labs/libevm/core/types"
 	"github.com/ava-labs/libevm/crypto"
 	"github.com/ava-labs/libevm/libevm/ethtest"
+	"github.com/ava-labs/libevm/libevm/pseudo"
 	"github.com/ava-labs/libevm/rlp"
 )
 
@@ -36,6 +37,8 @@ type stubHeaderHooks struct {
 	suffix                                   []byte
 	gotRawJSONToUnmarshal, gotRawRLPToDecode []byte
 	setHeaderToOnUnmarshalOrDecode           Header
+	accessor                                 pseudo.Accessor[*Header, *stubHeaderHooks]
+	toCopy                                   *stubHeaderHooks
 
 	errMarshal, errUnmarshal, errEncode, errDecode error
 }
@@ -75,6 +78,10 @@ func (hh *stubHeaderHooks) DecodeRLP(h *Header, s *rlp.Stream) error {
 	return hh.errDecode
 }
 
+func (hh *stubHeaderHooks) PostCopy(dst *Header) {
+	hh.accessor.Set(dst, hh.toCopy)
+}
+
 func TestHeaderHooks(t *testing.T) {
 	TestOnlyClearRegisteredExtras()
 	defer TestOnlyClearRegisteredExtras()
@@ -135,6 +142,20 @@ func TestHeaderHooks(t *testing.T) {
 		assert.Equalf(t, &stub.setHeaderToOnUnmarshalOrDecode, hdr, "%T after RLP decoding with hook", hdr)
 	})
 
+	t.Run("PostCopy", func(t *testing.T) {
+		hdr := new(Header)
+		stub := &stubHeaderHooks{
+			accessor: extras.Header,
+			toCopy: &stubHeaderHooks{
+				suffix: []byte("copied"),
+			},
+		}
+		extras.Header.Set(hdr, stub)
+
+		got := extras.Header.Get(CopyHeader(hdr))
+		assert.Equal(t, stub.toCopy, got)
+	})
+
 	t.Run("error_propagation", func(t *testing.T) {
 		errMarshal := errors.New("whoops")
 		errUnmarshal := errors.New("is it broken?")