From b81735924936291303559fd71dabaa1aa88f57c5 Mon Sep 17 00:00:00 2001 From: Joe Tsai Date: Fri, 21 Jul 2017 16:53:54 -0700 Subject: encoding/json: ignore embedded fields of pointers to unexported non-structs https://golang.org/cl/33773 fixes the JSON marshaler to avoid serializing embedded fields on unexported types of non-struct types. However, Go allows embedding pointer to types, so the check for whether the field is a non-struct type must first dereference the pointer to get at the underlying type. Furthermore, due to a edge-case in the behavior of StructField.PkgPath not being a reliable indicator of whether the field is unexported (see #21122), we use our own logic to determine whether the field is exported or not. The logic in this CL may be simplified depending on what happens in #21122. Fixes #21121 Updates #21122 Change-Id: I8dfd1cdfac8a87950df294a566fb96dfd04fd749 Reviewed-on: https://go-review.googlesource.com/50711 Reviewed-by: Ian Lance Taylor Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot --- src/encoding/json/encode.go | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) (limited to 'src/encoding/json/encode.go') diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go index 6fcea4735f..0371f0a24d 100644 --- a/src/encoding/json/encode.go +++ b/src/encoding/json/encode.go @@ -1093,7 +1093,22 @@ func typeFields(t reflect.Type) []field { // Scan f.typ for fields to include. for i := 0; i < f.typ.NumField(); i++ { sf := f.typ.Field(i) - if sf.PkgPath != "" && (!sf.Anonymous || sf.Type.Kind() != reflect.Struct) { // unexported + if sf.Anonymous { + t := sf.Type + if t.Kind() == reflect.Ptr { + t = t.Elem() + } + // If embedded, StructField.PkgPath is not a reliable + // indicator of whether the field is exported. + // See https://golang.org/issue/21122 + if !isExported(t.Name()) && t.Kind() != reflect.Struct { + // Ignore embedded fields of unexported non-struct types. + // Do not ignore embedded fields of unexported struct types + // since they may have exported fields. + continue + } + } else if sf.PkgPath != "" { + // Ignore unexported non-embedded fields. continue } tag := sf.Tag.Get("json") @@ -1211,6 +1226,12 @@ func typeFields(t reflect.Type) []field { return fields } +// isExported reports whether the identifier is exported. +func isExported(id string) bool { + r, _ := utf8.DecodeRuneInString(id) + return unicode.IsUpper(r) +} + // dominantField looks through the fields, all of which are known to // have the same name, to find the single field that dominates the // others using Go's embedding rules, modified by the presence of -- cgit v1.3