From 47b7f4a5a286e431e8e0a5cfe41fedf1e5f317da Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Tue, 24 Nov 2020 20:15:11 +0900
Subject: [PATCH] Fix decoding for UnmarshalJSON / UnmarshalText

---
 decode_compile.go        | 16 ++++++++--------
 decode_struct.go         |  3 +++
 decode_unmarshal_json.go | 22 ++++++++++++++++++++--
 decode_unmarshal_text.go | 22 +++++++++++++++++++---
 4 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/decode_compile.go b/decode_compile.go
index be51732..8d92f5d 100644
--- a/decode_compile.go
+++ b/decode_compile.go
@@ -9,13 +9,13 @@ import (
 func (d *Decoder) compileHead(typ *rtype) (decoder, error) {
 	switch {
 	case typ.Implements(unmarshalJSONType):
-		return newUnmarshalJSONDecoder(typ), nil
+		return newUnmarshalJSONDecoder(typ, "", ""), nil
 	case rtype_ptrTo(typ).Implements(unmarshalJSONType):
-		return newUnmarshalJSONDecoder(rtype_ptrTo(typ)), nil
+		return newUnmarshalJSONDecoder(rtype_ptrTo(typ), "", ""), nil
 	case typ.Implements(unmarshalTextType):
-		return newUnmarshalTextDecoder(typ), nil
+		return newUnmarshalTextDecoder(typ, "", ""), nil
 	case rtype_ptrTo(typ).Implements(unmarshalTextType):
-		return newUnmarshalTextDecoder(rtype_ptrTo(typ)), nil
+		return newUnmarshalTextDecoder(rtype_ptrTo(typ), "", ""), nil
 	}
 	return d.compile(typ.Elem(), "", "")
 }
@@ -23,13 +23,13 @@ func (d *Decoder) compileHead(typ *rtype) (decoder, error) {
 func (d *Decoder) compile(typ *rtype, structName, fieldName string) (decoder, error) {
 	switch {
 	case typ.Implements(unmarshalJSONType):
-		return newUnmarshalJSONDecoder(typ), nil
+		return newUnmarshalJSONDecoder(typ, structName, fieldName), nil
 	case rtype_ptrTo(typ).Implements(unmarshalJSONType):
-		return newUnmarshalJSONDecoder(rtype_ptrTo(typ)), nil
+		return newUnmarshalJSONDecoder(rtype_ptrTo(typ), structName, fieldName), nil
 	case typ.Implements(unmarshalTextType):
-		return newUnmarshalTextDecoder(typ), nil
+		return newUnmarshalTextDecoder(typ, structName, fieldName), nil
 	case rtype_ptrTo(typ).Implements(unmarshalTextType):
-		return newUnmarshalTextDecoder(rtype_ptrTo(typ)), nil
+		return newUnmarshalTextDecoder(rtype_ptrTo(typ), structName, fieldName), nil
 	}
 
 	switch typ.Kind() {
diff --git a/decode_struct.go b/decode_struct.go
index 34854c1..10f0330 100644
--- a/decode_struct.go
+++ b/decode_struct.go
@@ -35,6 +35,9 @@ func (d *structDecoder) decodeStream(s *stream, p unsafe.Pointer) error {
 		return errNotAtBeginningOfValue(s.totalOffset())
 	}
 	s.cursor++
+	if s.char() == '}' {
+		return nil
+	}
 	for {
 		s.reset()
 		key, err := d.keyDecoder.decodeStreamByte(s)
diff --git a/decode_unmarshal_json.go b/decode_unmarshal_json.go
index c3274e6..595b70f 100644
--- a/decode_unmarshal_json.go
+++ b/decode_unmarshal_json.go
@@ -7,10 +7,24 @@ import (
 type unmarshalJSONDecoder struct {
 	typ             *rtype
 	isDoublePointer bool
+	structName      string
+	fieldName       string
 }
 
-func newUnmarshalJSONDecoder(typ *rtype) *unmarshalJSONDecoder {
-	return &unmarshalJSONDecoder{typ: typ}
+func newUnmarshalJSONDecoder(typ *rtype, structName, fieldName string) *unmarshalJSONDecoder {
+	return &unmarshalJSONDecoder{
+		typ:        typ,
+		structName: structName,
+		fieldName:  fieldName,
+	}
+}
+
+func (d *unmarshalJSONDecoder) annotateError(err error) {
+	ut, ok := err.(*UnmarshalTypeError)
+	if ok {
+		ut.Struct = d.structName
+		ut.Field = d.fieldName
+	}
 }
 
 func (d *unmarshalJSONDecoder) decodeStream(s *stream, p unsafe.Pointer) error {
@@ -27,6 +41,7 @@ func (d *unmarshalJSONDecoder) decodeStream(s *stream, p unsafe.Pointer) error {
 			ptr: newptr,
 		}))
 		if err := v.(Unmarshaler).UnmarshalJSON(src); err != nil {
+			d.annotateError(err)
 			return err
 		}
 		*(*unsafe.Pointer)(p) = newptr
@@ -36,6 +51,7 @@ func (d *unmarshalJSONDecoder) decodeStream(s *stream, p unsafe.Pointer) error {
 			ptr: p,
 		}))
 		if err := v.(Unmarshaler).UnmarshalJSON(src); err != nil {
+			d.annotateError(err)
 			return err
 		}
 	}
@@ -57,6 +73,7 @@ func (d *unmarshalJSONDecoder) decode(buf []byte, cursor int64, p unsafe.Pointer
 			ptr: newptr,
 		}))
 		if err := v.(Unmarshaler).UnmarshalJSON(src); err != nil {
+			d.annotateError(err)
 			return 0, err
 		}
 		*(*unsafe.Pointer)(p) = newptr
@@ -66,6 +83,7 @@ func (d *unmarshalJSONDecoder) decode(buf []byte, cursor int64, p unsafe.Pointer
 			ptr: p,
 		}))
 		if err := v.(Unmarshaler).UnmarshalJSON(src); err != nil {
+			d.annotateError(err)
 			return 0, err
 		}
 	}
diff --git a/decode_unmarshal_text.go b/decode_unmarshal_text.go
index 5b25834..d60b521 100644
--- a/decode_unmarshal_text.go
+++ b/decode_unmarshal_text.go
@@ -9,11 +9,25 @@ import (
 )
 
 type unmarshalTextDecoder struct {
-	typ *rtype
+	typ        *rtype
+	structName string
+	fieldName  string
 }
 
-func newUnmarshalTextDecoder(typ *rtype) *unmarshalTextDecoder {
-	return &unmarshalTextDecoder{typ: typ}
+func newUnmarshalTextDecoder(typ *rtype, structName, fieldName string) *unmarshalTextDecoder {
+	return &unmarshalTextDecoder{
+		typ:        typ,
+		structName: structName,
+		fieldName:  fieldName,
+	}
+}
+
+func (d *unmarshalTextDecoder) annotateError(err error) {
+	ut, ok := err.(*UnmarshalTypeError)
+	if ok {
+		ut.Struct = d.structName
+		ut.Field = d.fieldName
+	}
 }
 
 func (d *unmarshalTextDecoder) decodeStream(s *stream, p unsafe.Pointer) error {
@@ -32,6 +46,7 @@ func (d *unmarshalTextDecoder) decodeStream(s *stream, p unsafe.Pointer) error {
 		ptr: newptr,
 	}))
 	if err := v.(encoding.TextUnmarshaler).UnmarshalText(src); err != nil {
+		d.annotateError(err)
 		return err
 	}
 	*(*unsafe.Pointer)(p) = newptr
@@ -54,6 +69,7 @@ func (d *unmarshalTextDecoder) decode(buf []byte, cursor int64, p unsafe.Pointer
 		ptr: *(*unsafe.Pointer)(unsafe.Pointer(&p)),
 	}))
 	if err := v.(encoding.TextUnmarshaler).UnmarshalText(src); err != nil {
+		d.annotateError(err)
 		return 0, err
 	}
 	return end, nil