test: pseudo.Type.EncodeRLP()

Author: ARR4N

libevm/ethtest/rand.go

@@ -13,11 +13,13 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see
 // <http://www.gnu.org/licenses/>.
+
 package ethtest
 
 import (
 	"math/big"
 
+	"github.com/holiman/uint256"
 	"golang.org/x/exp/rand"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -33,9 +35,16 @@ func NewPseudoRand(seed uint64) *PseudoRand {
 	return &PseudoRand{rand.New(rand.NewSource(seed))}
 }
 
+// Read is equivalent to [rand.Rand.Read] except that it doesn't return an error
+// because it is guaranteed to be nil.
+func (r *PseudoRand) Read(p []byte) int {
+	n, _ := r.Rand.Read(p) // Guaranteed nil error
+	return n
+}
+
 // Address returns a pseudorandom address.
 func (r *PseudoRand) Address() (a common.Address) {
-	r.Read(a[:]) //nolint:gosec,errcheck // Guaranteed nil error
+	r.Read(a[:])
 	return a
 }
 
@@ -47,18 +56,35 @@ func (r *PseudoRand) AddressPtr() *common.Address {
 
 // Hash returns a pseudorandom hash.
 func (r *PseudoRand) Hash() (h common.Hash) {
-	r.Read(h[:]) //nolint:gosec,errcheck // Guaranteed nil error
+	r.Read(h[:])
 	return h
 }
 
+// HashPtr returns a pointer to a pseudorandom hash.
+func (r *PseudoRand) HashPtr() *common.Hash {
+	h := r.Hash()
+	return &h
+}
+
 // Bytes returns `n` pseudorandom bytes.
 func (r *PseudoRand) Bytes(n uint) []byte {
 	b := make([]byte, n)
-	r.Read(b) //nolint:gosec,errcheck // Guaranteed nil error
+	r.Read(b)
 	return b
 }
 
 // Big returns [rand.Rand.Uint64] as a [big.Int].
 func (r *PseudoRand) BigUint64() *big.Int {
 	return new(big.Int).SetUint64(r.Uint64())
 }
+
+// Uint64Ptr returns a pointer to a pseudorandom uint64.
+func (r *PseudoRand) Uint64Ptr() *uint64 {
+	u := r.Uint64()
+	return &u
+}
+
+// Uint256 returns a random 256-bit unsigned int.
+func (r *PseudoRand) Uint256() *uint256.Int {
+	return new(uint256.Int).SetBytes(r.Bytes(32))
+}

libevm/pseudo/rlp_test.go

@@ -0,0 +1,68 @@
+// Copyright 2024 the libevm authors.
+//
+// The libevm additions to go-ethereum are free software: you can redistribute
+// them and/or modify them under the terms of the GNU Lesser General Public License
+// as published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The libevm additions are distributed in the hope that they will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package pseudo_test
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/libevm/ethtest"
+	"github.com/ethereum/go-ethereum/libevm/pseudo"
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+func TestRLPEquivalence(t *testing.T) {
+	t.Parallel()
+
+	for seed := uint64(0); seed < 20; seed++ {
+		rng := ethtest.NewPseudoRand(seed)
+
+		t.Run("fuzz", func(t *testing.T) {
+			t.Parallel()
+
+			hdr := &types.Header{
+				ParentHash:  rng.Hash(),
+				UncleHash:   rng.Hash(),
+				Coinbase:    rng.Address(),
+				Root:        rng.Hash(),
+				TxHash:      rng.Hash(),
+				ReceiptHash: rng.Hash(),
+				Difficulty:  big.NewInt(rng.Int63()),
+				Number:      big.NewInt(rng.Int63()),
+				GasLimit:    rng.Uint64(),
+				GasUsed:     rng.Uint64(),
+				Time:        rng.Uint64(),
+				Extra:       rng.Bytes(uint(rng.Uint64n(128))),
+				MixDigest:   rng.Hash(),
+			}
+			rng.Read(hdr.Bloom[:])
+			rng.Read(hdr.Nonce[:])
+
+			want, err := rlp.EncodeToBytes(hdr)
+			require.NoErrorf(t, err, "rlp.EncodeToBytes(%T)", hdr)
+
+			typ := pseudo.From(hdr).Type
+			got, err := rlp.EncodeToBytes(typ)
+			require.NoErrorf(t, err, "rlp.EncodeToBytes(%T)", typ)
+
+			require.Equalf(t, want, got, "RLP encoding of %T (canonical) vs %T (under test)", hdr, typ)
+		})
+	}
+}

libevm/pseudo/type.go

@@ -142,8 +142,10 @@ func (v *Value[T]) MarshalJSON() ([]byte, error) { return v.t.MarshalJSON() }
 // UnmarshalJSON implements the [json.Unmarshaler] interface.
 func (v *Value[T]) UnmarshalJSON(b []byte) error { return v.t.UnmarshalJSON(b) }
 
+// EncodeRLP implements the [rlp.Encoder] interface.
 func (t *Type) EncodeRLP(w io.Writer) error { return t.val.EncodeRLP(w) }
 
+// DecodeRLP implements the [rlp.Decoder] interface.
 func (t *Type) DecodeRLP(s *rlp.Stream) error { return t.val.DecodeRLP(s) }
 
 var _ = []interface {