From 2db7369d6d80338acae434f8d45647272c6ba24c Mon Sep 17 00:00:00 2001
From: Ryan Tinianov <tinianov@live.com>
Date: Wed, 12 Jun 2024 13:47:29 -0400
Subject: [PATCH] Fix decoding unnamed params, the return type was right, but
 names weren't populated for the arg itself. (#13512)

---
 core/services/relay/evm/codec_test.go         | 27 +++++++++++++++++++
 core/services/relay/evm/decoder.go            |  8 +++++-
 core/services/relay/evm/types/codec_entry.go  |  2 ++
 .../relay/evm/types/codec_entry_test.go       |  7 +++++
 4 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/core/services/relay/evm/codec_test.go b/core/services/relay/evm/codec_test.go
index c80002ebd70..638a9afd706 100644
--- a/core/services/relay/evm/codec_test.go
+++ b/core/services/relay/evm/codec_test.go
@@ -34,6 +34,33 @@ func TestCodec(t *testing.T) {
 
 	anyN := 10
 	c := tester.GetCodec(t)
+	t.Run("Decode works with multiple unnamed return values", func(t *testing.T) {
+		encode := &struct {
+			F0 int32
+			F1 int32
+		}{F0: 1, F1: 2}
+		codecName := "my_codec"
+		evmEncoderConfig := `[{"Name":"","Type":"int32"},{"Name":"","Type":"int32"}]`
+
+		codecConfig := types.CodecConfig{Configs: map[string]types.ChainCodecConfig{
+			codecName: {TypeABI: evmEncoderConfig},
+		}}
+		c, err := evm.NewCodec(codecConfig)
+		require.NoError(t, err)
+
+		result, err := c.Encode(testutils.Context(t), encode, codecName)
+		require.NoError(t, err)
+
+		decode := &struct {
+			F0 int32
+			F1 int32
+		}{}
+		err = c.Decode(testutils.Context(t), result, decode, codecName)
+		require.NoError(t, err)
+		require.Equal(t, encode.F0, decode.F0)
+		require.Equal(t, encode.F1, decode.F1)
+	})
+
 	t.Run("GetMaxEncodingSize delegates to GetMaxSize", func(t *testing.T) {
 		actual, err := c.GetMaxEncodingSize(testutils.Context(t), anyN, sizeItemType)
 		assert.NoError(t, err)
diff --git a/core/services/relay/evm/decoder.go b/core/services/relay/evm/decoder.go
index f16875d80f6..fdecf002020 100644
--- a/core/services/relay/evm/decoder.go
+++ b/core/services/relay/evm/decoder.go
@@ -18,7 +18,13 @@ type decoder struct {
 
 var _ commontypes.Decoder = &decoder{}
 
-func (m *decoder) Decode(_ context.Context, raw []byte, into any, itemType string) error {
+func (m *decoder) Decode(_ context.Context, raw []byte, into any, itemType string) (err error) {
+	defer func() {
+		// unexpected, but reflection can panic
+		if r := recover(); r != nil {
+			err = fmt.Errorf("%w: %v", commontypes.ErrInvalidType, r)
+		}
+	}()
 	info, ok := m.Definitions[itemType]
 	if !ok {
 		return fmt.Errorf("%w: cannot find definition for %s", commontypes.ErrInvalidType, itemType)
diff --git a/core/services/relay/evm/types/codec_entry.go b/core/services/relay/evm/types/codec_entry.go
index b42bf9c0b08..38242c43a2d 100644
--- a/core/services/relay/evm/types/codec_entry.go
+++ b/core/services/relay/evm/types/codec_entry.go
@@ -146,11 +146,13 @@ func (entry *codecEntry) Init() (err error) {
 			}
 			for {
 				name = name + "_X"
+				arg.Name = name
 				if !seenNames[name] {
 					break
 				}
 			}
 		}
+		args[i] = arg
 		seenNames[name] = true
 		native[i] = reflect.StructField{Name: name, Type: nativeArg}
 		checked[i] = reflect.StructField{Name: name, Type: checkedArg}
diff --git a/core/services/relay/evm/types/codec_entry_test.go b/core/services/relay/evm/types/codec_entry_test.go
index da1d4cc22a5..06b08fcecf2 100644
--- a/core/services/relay/evm/types/codec_entry_test.go
+++ b/core/services/relay/evm/types/codec_entry_test.go
@@ -219,11 +219,15 @@ func TestCodecEntry(t *testing.T) {
 		assert.NoError(t, entry.Init())
 		ct := entry.CheckedType()
 		require.Equal(t, 2, ct.NumField())
+		args := entry.Args()
+		require.Equal(t, 2, len(args))
 		f0 := ct.Field(0)
 		assert.Equal(t, "F0", f0.Name)
+		assert.Equal(t, "F0", args[0].Name)
 		assert.Equal(t, reflect.TypeOf((*int64)(nil)), f0.Type)
 		f1 := ct.Field(1)
 		assert.Equal(t, "F1", f1.Name)
+		assert.Equal(t, "F1", args[1].Name)
 		assert.Equal(t, reflect.TypeOf((*int32)(nil)), f1.Type)
 	})
 
@@ -237,11 +241,14 @@ func TestCodecEntry(t *testing.T) {
 		assert.NoError(t, entry.Init())
 		ct := entry.CheckedType()
 		require.Equal(t, 2, ct.NumField())
+		args := entry.Args()
+		require.Equal(t, 2, len(args))
 		f0 := ct.Field(0)
 		assert.Equal(t, "F1", f0.Name)
 		assert.Equal(t, reflect.TypeOf((*int64)(nil)), f0.Type)
 		f1 := ct.Field(1)
 		assert.Equal(t, "F1_X", f1.Name)
+		assert.Equal(t, "F1_X", args[1].Name)
 		assert.Equal(t, reflect.TypeOf((*int32)(nil)), f1.Type)
 	})