From ab046b2afa9c3ea4a480b087e7fdf2f1d599aaf2 Mon Sep 17 00:00:00 2001
From: Andrew Gerrand <adg@golang.org>
Date: Mon, 19 Sep 2011 11:54:29 +1000
Subject: [PATCH] [release-branch.r60] json: fix decode bug with struct tag
 names with ,opts being ignored
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««« CL 4965049 / f8e4df3c4048
json: fix decode bug with struct tag names with ,opts being ignored

When the encoder was updated to respect the ",omitempty"
struct tag options, the decoder half was never updated to know
about the new struct tag format. (the format is now an optional
name, followed by zero or more ",option" strings)

This only affected people who used ",omitempty" along with
a field name. In that case, the serialized JSON wouldn't
decode to the original value.

R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/4965049
»»»

R=dsymonds
CC=golang-dev
https://golang.org/cl/5029043
---
 src/pkg/json/decode.go      | 12 +++++++++++-
 src/pkg/json/decode_test.go |  6 +++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/pkg/json/decode.go b/src/pkg/json/decode.go
index 4f6562bd55..6782c76c4e 100644
--- a/src/pkg/json/decode.go
+++ b/src/pkg/json/decode.go
@@ -486,7 +486,7 @@ func (d *decodeState) object(v reflect.Value) {
 			if isValidTag(key) {
 				for i := 0; i < sv.NumField(); i++ {
 					f = st.Field(i)
-					if f.Tag.Get("json") == key {
+					if tagName(f.Tag.Get("json")) == key {
 						ok = true
 						break
 					}
@@ -918,3 +918,13 @@ func unquoteBytes(s []byte) (t []byte, ok bool) {
 	}
 	return b[0:w], true
 }
+
+// tagName extracts the field name part out of the "json" struct tag
+// value. The json struct tag format is an optional name, followed by
+// zero or more ",option" values.
+func tagName(v string) string {
+	if idx := strings.Index(v, ","); idx != -1 {
+		return v[:idx]
+	}
+	return v
+}
diff --git a/src/pkg/json/decode_test.go b/src/pkg/json/decode_test.go
index a855d60486..4c179de5d0 100644
--- a/src/pkg/json/decode_test.go
+++ b/src/pkg/json/decode_test.go
@@ -262,7 +262,8 @@ type All struct {
 	Float32 float32
 	Float64 float64
 
-	Foo string `json:"bar"`
+	Foo  string `json:"bar"`
+	Foo2 string `json:"bar2,dummyopt"`
 
 	PBool    *bool
 	PInt     *int
@@ -331,6 +332,7 @@ var allValue = All{
 	Float32: 14.1,
 	Float64: 15.1,
 	Foo:     "foo",
+	Foo2:    "foo2",
 	String:  "16",
 	Map: map[string]Small{
 		"17": {Tag: "tag17"},
@@ -391,6 +393,7 @@ var allValueIndent = `{
 	"Float32": 14.1,
 	"Float64": 15.1,
 	"bar": "foo",
+	"bar2": "foo2",
 	"PBool": null,
 	"PInt": null,
 	"PInt8": null,
@@ -481,6 +484,7 @@ var pallValueIndent = `{
 	"Float32": 0,
 	"Float64": 0,
 	"bar": "",
+	"bar2": "",
 	"PBool": true,
 	"PInt": 2,
 	"PInt8": 3,
-- 
2.50.0