From 7b985a9175e70d6891ad85507e73c0140dc0d86d Mon Sep 17 00:00:00 2001
From: Nicolas Mahe <nicolas@mahe.me>
Date: Tue, 10 Sep 2019 18:06:50 +0700
Subject: [PATCH 1/3] Only bypass hash tag if it an type interface containing a
 struct or a pointer

---
 hash/structhash/structhash.go      |  2 +-
 hash/structhash/structhash_test.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/hash/structhash/structhash.go b/hash/structhash/structhash.go
index 0d50188dd..9de949619 100644
--- a/hash/structhash/structhash.go
+++ b/hash/structhash/structhash.go
@@ -102,7 +102,7 @@ func write(buf *bytes.Buffer, v reflect.Value) *bytes.Buffer {
 			// NOTE: structhash will allow to process all interface types.
 			// gogo/protobuf is not able to set tags for directly oneof interface.
 			// see: https://github.com/gogo/protobuf/issues/623
-			if to.name == "" && reflect.Zero(sf.Type).Kind() == reflect.Interface {
+			if to.name == "" && reflect.Zero(sf.Type).Kind() == reflect.Interface && (v.Field(i).Elem().Kind() == reflect.Struct || v.Field(i).Elem().Kind() == reflect.Ptr) {
 				to.skip = false
 				to.name = sf.Name
 			}
diff --git a/hash/structhash/structhash_test.go b/hash/structhash/structhash_test.go
index 5ac573f46..9434830ff 100644
--- a/hash/structhash/structhash_test.go
+++ b/hash/structhash/structhash_test.go
@@ -139,6 +139,34 @@ func TestDump(t *testing.T) {
 			}{b: false}},
 			"{a:{b:false}}",
 		},
+		{
+			struct {
+				a interface{}
+			}{
+				struct {
+					b int
+					c interface{}
+				}{
+					b: 1,
+					c: 2,
+				},
+			},
+			"{a:{}}",
+		},
+		{
+			struct {
+				a interface{}
+			}{
+				&struct {
+					b int         `hash:"name:b"`
+					c interface{} `hash:"name:c"`
+				}{
+					b: 1,
+					c: 2,
+				},
+			},
+			"{a:{b:1,c:2}}",
+		},
 	}
 
 	for _, tt := range tests {

From 417fc35ca9ee36f9bf59b562b3623b4deb772e96 Mon Sep 17 00:00:00 2001
From: Nicolas Mahe <nicolas@mahe.me>
Date: Tue, 10 Sep 2019 18:29:29 +0700
Subject: [PATCH 2/3] Only traverse pointer of struct for hash calculation

---
 hash/structhash/structhash.go      |  2 +-
 hash/structhash/structhash_test.go | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/hash/structhash/structhash.go b/hash/structhash/structhash.go
index 9de949619..9d706515b 100644
--- a/hash/structhash/structhash.go
+++ b/hash/structhash/structhash.go
@@ -102,7 +102,7 @@ func write(buf *bytes.Buffer, v reflect.Value) *bytes.Buffer {
 			// NOTE: structhash will allow to process all interface types.
 			// gogo/protobuf is not able to set tags for directly oneof interface.
 			// see: https://github.com/gogo/protobuf/issues/623
-			if to.name == "" && reflect.Zero(sf.Type).Kind() == reflect.Interface && (v.Field(i).Elem().Kind() == reflect.Struct || v.Field(i).Elem().Kind() == reflect.Ptr) {
+			if to.name == "" && reflect.Zero(sf.Type).Kind() == reflect.Interface && (v.Field(i).Elem().Kind() == reflect.Struct || (v.Field(i).Elem().Kind() == reflect.Ptr && v.Field(i).Elem().Elem().Kind() == reflect.Struct)) {
 				to.skip = false
 				to.name = sf.Name
 			}
diff --git a/hash/structhash/structhash_test.go b/hash/structhash/structhash_test.go
index 9434830ff..b3ea85ec3 100644
--- a/hash/structhash/structhash_test.go
+++ b/hash/structhash/structhash_test.go
@@ -22,6 +22,7 @@ func TestMd5(t *testing.T) {
 
 //nolint:megacheck
 func TestDump(t *testing.T) {
+	int1 := int(1)
 	tests := []struct {
 		v interface{}
 		s string
@@ -167,6 +168,20 @@ func TestDump(t *testing.T) {
 			},
 			"{a:{b:1,c:2}}",
 		},
+		{
+			struct {
+				a interface{}
+			}{
+				&struct {
+					b *int
+					c interface{}
+				}{
+					b: &int1,
+					c: &int1,
+				},
+			},
+			"{a:{}}",
+		},
 	}
 
 	for _, tt := range tests {

From ea408ca241736635aa6b054ec4100edb54887b83 Mon Sep 17 00:00:00 2001
From: Nicolas Mahe <nicolas@mahe.me>
Date: Tue, 10 Sep 2019 18:34:51 +0700
Subject: [PATCH 3/3] add tests

---
 hash/structhash/structhash_test.go | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/hash/structhash/structhash_test.go b/hash/structhash/structhash_test.go
index b3ea85ec3..b7c86a513 100644
--- a/hash/structhash/structhash_test.go
+++ b/hash/structhash/structhash_test.go
@@ -182,6 +182,26 @@ func TestDump(t *testing.T) {
 			},
 			"{a:{}}",
 		},
+		{
+			struct {
+				a interface{}
+			}{
+				&struct {
+					b *int
+					c interface{}
+				}{
+					b: nil,
+					c: nil,
+				},
+			},
+			"{a:{}}",
+		},
+		{
+			struct {
+				a interface{}
+			}{nil},
+			"{}",
+		},
 	}
 
 	for _, tt := range tests {