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author | Cuong Manh Le <cuong.manhle.vn@gmail.com> | 2019-10-10 10:19:12 +0700 |
---|---|---|
committer | Daniel Martà <mvdan@mvdan.cc> | 2019-10-10 12:59:11 +0000 |
commit | fb9af8411eaa3e38d2f72e28a305772f50042657 (patch) | |
tree | f09dadcefa10828ec8c8e7364c4d1383c67748a9 /src/encoding/json | |
parent | 900ebcfe4d592486dd5bc50f5e8101ba65e32948 (diff) | |
download | go-fb9af8411eaa3e38d2f72e28a305772f50042657.tar.gz go-fb9af8411eaa3e38d2f72e28a305772f50042657.zip |
encoding/json: support TextUnmarshaler for map keys with string underlying types
When unmarshaling to a map, the map's key type must either be a string,
an integer, or implement encoding.TextUnmarshaler. But for a user
defined type, reflect.Kind will not distinguish between the static type
and the underlying type. In:
var x MyString = "x"
t := reflect.TypeOf(x)
println(t.Kind() == reflect.String)
the Kind of x is still reflect.String, even though the static type of x
is MyString.
Moreover, checking for the map's key type is a string occurs first, so
even if the map key type MyString implements encoding.TextUnmarshaler,
it will be ignored.
To fix the bug, check for encoding.TextUnmarshaler first.
Fixes #34437
Change-Id: I780e0b084575e1dddfbb433fe03857adf71d05fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/200237
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martà <mvdan@mvdan.cc>
Diffstat (limited to 'src/encoding/json')
-rw-r--r-- | src/encoding/json/decode.go | 4 | ||||
-rw-r--r-- | src/encoding/json/decode_test.go | 20 |
2 files changed, 22 insertions, 2 deletions
diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go index 407fbcedbe..86d8a69db7 100644 --- a/src/encoding/json/decode.go +++ b/src/encoding/json/decode.go @@ -773,14 +773,14 @@ func (d *decodeState) object(v reflect.Value) error { kt := t.Key() var kv reflect.Value switch { - case kt.Kind() == reflect.String: - kv = reflect.ValueOf(key).Convert(kt) case reflect.PtrTo(kt).Implements(textUnmarshalerType): kv = reflect.New(kt) if err := d.literalStore(item, kv, true); err != nil { return err } kv = kv.Elem() + case kt.Kind() == reflect.String: + kv = reflect.ValueOf(key).Convert(kt) default: switch kt.Kind() { case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go index 4cbd2172d0..498bd97b46 100644 --- a/src/encoding/json/decode_test.go +++ b/src/encoding/json/decode_test.go @@ -2411,3 +2411,23 @@ func TestUnmarshalRecursivePointer(t *testing.T) { t.Fatal(err) } } + +type textUnmarshalerString string + +func (m *textUnmarshalerString) UnmarshalText(text []byte) error { + *m = textUnmarshalerString(strings.ToLower(string(text))) + return nil +} + +// Test unmarshal to a map, with map key is a user defined type. +// See golang.org/issues/34437. +func TestUnmarshalMapWithTextUnmarshalerStringKey(t *testing.T) { + var p map[textUnmarshalerString]string + if err := Unmarshal([]byte(`{"FOO": "1"}`), &p); err != nil { + t.Fatalf("Unmarshal unexpected error: %v", err) + } + + if _, ok := p["foo"]; !ok { + t.Errorf(`Key "foo" is not existed in map: %v`, p) + } +} |