code review 4645069: reflect: support for struct tag use by multiple packages

src/pkg/asn1/marshal.go

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package asn1
 
 import (
         "big"
         "bytes"
         "fmt"
@@ skipping 395 matching lines @@
                                 _, err = out.Write(stripTagAndLength(bytes))
                                 return
                         } else {
                                 startingField = 1
                         }
                 }
 
                 for i := startingField; i < t.NumField(); i++ {
                         var pre *forkableWriter
                         pre, out = out.fork()
-                        err = marshalField(pre, v.Field(i), parseFieldParameters(t.Field(i).Tag))
+                        err = marshalField(pre, v.Field(i), parseFieldParameters(t.Field(i).Tag.Get("asn1")))
                         if err != nil {
                                 return
                         }
                 }
                 return
         case reflect.Slice:
                 sliceType := v.Type()
                 if sliceType.Elem().Kind() == reflect.Uint8 {
                         bytes := make([]byte, v.Len())
                         for i := 0; i < v.Len(); i++ {
@@ skipping 108 matching lines @@
         var out bytes.Buffer
         v := reflect.ValueOf(val)
         f := newForkableWriter()
         err := marshalField(f, v, fieldParameters{})
         if err != nil {
                 return nil, err
         }
         _, err = f.writeTo(&out)
         return out.Bytes(), nil
 }