From e38c3606b3daa474e416864f13fe78da84a763a6 Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Mon, 29 Mar 2021 02:28:04 +0900
Subject: [PATCH 1/3] Fix decoding of slice pointer type

---
 decode_slice.go |  8 ++++++--
 decode_test.go  | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/decode_slice.go b/decode_slice.go
index 0442a75..e70588e 100644
--- a/decode_slice.go
+++ b/decode_slice.go
@@ -114,7 +114,9 @@ func (d *sliceDecoder) decodeStream(s *stream, depth int64, p unsafe.Pointer) er
 					dst := sliceHeader{data: data, len: idx, cap: capacity}
 					copySlice(d.elemType, dst, src)
 				}
-				if err := d.valueDecoder.decodeStream(s, depth, unsafe.Pointer(uintptr(data)+uintptr(idx)*d.size)); err != nil {
+				ep := unsafe.Pointer(uintptr(data) + uintptr(idx)*d.size)
+				*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+				if err := d.valueDecoder.decodeStream(s, depth, ep); err != nil {
 					return err
 				}
 				s.skipWhiteSpace()
@@ -224,7 +226,9 @@ func (d *sliceDecoder) decode(buf []byte, cursor, depth int64, p unsafe.Pointer)
 					dst := sliceHeader{data: data, len: idx, cap: capacity}
 					copySlice(d.elemType, dst, src)
 				}
-				c, err := d.valueDecoder.decode(buf, cursor, depth, unsafe.Pointer(uintptr(data)+uintptr(idx)*d.size))
+				ep := unsafe.Pointer(uintptr(data) + uintptr(idx)*d.size)
+				*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+				c, err := d.valueDecoder.decode(buf, cursor, depth, ep)
 				if err != nil {
 					return 0, err
 				}
diff --git a/decode_test.go b/decode_test.go
index d76cf5c..6595f4b 100644
--- a/decode_test.go
+++ b/decode_test.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 	"testing"
 	"time"
+	"unsafe"
 
 	"github.com/goccy/go-json"
 )
@@ -2903,3 +2904,28 @@ func TestUnmarshalMaxDepth(t *testing.T) {
 		}
 	}
 }
+
+func TestDecodeSlice(t *testing.T) {
+	type B struct{ Int int32 }
+	type A struct{ B *B }
+	type X struct{ A []*A }
+
+	w1 := &X{}
+	w2 := &X{}
+
+	if err := json.Unmarshal([]byte(`{"a": [ {"b":{"int": 42} } ] }`), w1); err != nil {
+		t.Fatal(err)
+	}
+	w1addr := uintptr(unsafe.Pointer(w1.A[0].B))
+
+	if err := json.Unmarshal([]byte(`{"a": [ {"b":{"int": 112} } ] }`), w2); err != nil {
+		t.Fatal(err)
+	}
+	if uintptr(unsafe.Pointer(w1.A[0].B)) != w1addr {
+		t.Fatal("wrong addr")
+	}
+	w2addr := uintptr(unsafe.Pointer(w2.A[0].B))
+	if w1addr == w2addr {
+		t.Fatal("invaid address")
+	}
+}

From e660ae468de69b0649edb02860137b3a0093fd3d Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Mon, 29 Mar 2021 02:44:49 +0900
Subject: [PATCH 2/3] Fix pointer alignment error

---
 decode_slice.go | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/decode_slice.go b/decode_slice.go
index e70588e..d9a6749 100644
--- a/decode_slice.go
+++ b/decode_slice.go
@@ -7,12 +7,13 @@ import (
 )
 
 type sliceDecoder struct {
-	elemType     *rtype
-	valueDecoder decoder
-	size         uintptr
-	arrayPool    sync.Pool
-	structName   string
-	fieldName    string
+	elemType          *rtype
+	isElemPointerType bool
+	valueDecoder      decoder
+	size              uintptr
+	arrayPool         sync.Pool
+	structName        string
+	fieldName         string
 }
 
 // If use reflect.SliceHeader, data type is uintptr.
@@ -30,9 +31,10 @@ const (
 
 func newSliceDecoder(dec decoder, elemType *rtype, size uintptr, structName, fieldName string) *sliceDecoder {
 	return &sliceDecoder{
-		valueDecoder: dec,
-		elemType:     elemType,
-		size:         size,
+		valueDecoder:      dec,
+		elemType:          elemType,
+		isElemPointerType: elemType.Kind() == reflect.Ptr,
+		size:              size,
 		arrayPool: sync.Pool{
 			New: func() interface{} {
 				return &sliceHeader{
@@ -115,7 +117,9 @@ func (d *sliceDecoder) decodeStream(s *stream, depth int64, p unsafe.Pointer) er
 					copySlice(d.elemType, dst, src)
 				}
 				ep := unsafe.Pointer(uintptr(data) + uintptr(idx)*d.size)
-				*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+				if d.isElemPointerType {
+					*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+				}
 				if err := d.valueDecoder.decodeStream(s, depth, ep); err != nil {
 					return err
 				}
@@ -227,7 +231,9 @@ func (d *sliceDecoder) decode(buf []byte, cursor, depth int64, p unsafe.Pointer)
 					copySlice(d.elemType, dst, src)
 				}
 				ep := unsafe.Pointer(uintptr(data) + uintptr(idx)*d.size)
-				*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+				if d.isElemPointerType {
+					*(*unsafe.Pointer)(ep) = nil // initialize elem pointer
+				}
 				c, err := d.valueDecoder.decode(buf, cursor, depth, ep)
 				if err != nil {
 					return 0, err

From bfbfa474d6f31989754ae6510f9b0d96f9bd7b53 Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Mon, 29 Mar 2021 02:57:41 +0900
Subject: [PATCH 3/3] Add map type to initialize type list

---
 decode_slice.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/decode_slice.go b/decode_slice.go
index d9a6749..ea09f88 100644
--- a/decode_slice.go
+++ b/decode_slice.go
@@ -33,7 +33,7 @@ func newSliceDecoder(dec decoder, elemType *rtype, size uintptr, structName, fie
 	return &sliceDecoder{
 		valueDecoder:      dec,
 		elemType:          elemType,
-		isElemPointerType: elemType.Kind() == reflect.Ptr,
+		isElemPointerType: elemType.Kind() == reflect.Ptr || elemType.Kind() == reflect.Map,
 		size:              size,
 		arrayPool: sync.Pool{
 			New: func() interface{} {