codecgen ignores struct tags for struct field renaming

[starJammer]

Hi, I've been looking at codec recently and was testing it out but was getting some behavior differences between it and encoding/json. Here is the output I'm getting using the same structs.

Encodings from codec generated selfer code....
{"Key":"thing"}
{"Key":"whynot","Field1":"another"}
Encodings from codec reflection based encoding....
{"_key":"thing"}
{"_id":"another","_key":"whynot"}
Encodings from encoding/json....
{"_key":"thing"}
{"_key":"whynot","_id":"another"}

Below is my example code and directory structure

root
|----main.go
|----model
|--------model.go

The main.go file

package main

import (
    "fmt"
    "github.com/ugorji/go/codec" 
    "encoding/json"
    "./model"
)

type Test struct {
    Key string `json:"_key,omitempty"`
}

type Next struct {
    Test
    Field1 string `json:"_id,omitempty"`
    Field2 string `json:",omitempty"`
}


func main() {
    var h codec.Handle = new(codec.JsonHandle)
    var b []byte

    d := &model.Test{ Key : "thing" }
    u := &model.Next{ Field1: "another" }

    f := &Test{ Key : "thing" }
    t := &Next{ Field1: "another" }

    u.Key = "whynot"
    t.Key = "whynot" //Edited to add this line since it was missing

    fmt.Println( "Encodings from codec generated selfer code...." )
    b, _ = encodeCodec( d, h )
    fmt.Println( string(b) )
    b, _ = encodeCodec( u, h )
    fmt.Println( string(b) )

    fmt.Println( "Encodings from codec reflection based encoding...." )
    b, _ = encodeCodec( f, h )
    fmt.Println( string(b) )
    b, _ = encodeCodec( t, h )
    fmt.Println( string(b) )

    fmt.Println( "Encodings from encoding/json...." )
    b, _ = encodeJson( d )
    fmt.Println( string(b) )
    b, _ = encodeJson( u )
    fmt.Println( string(b) )

}

func encodeCodec( v interface{}, h codec.Handle ) ( []byte, error ) {
    var b []byte
    enc := codec.NewEncoderBytes( &b, h )
    err := enc.Encode( v )
    if err != nil {
        fmt.Println( err )
        return nil, err
    }
    return b, nil
}

func encodeJson( v interface{} ) ( []byte, error ){
    b, err := json.Marshal( v )

    if err != nil {
        fmt.Println( err )
        return nil, err
    }
    return b, nil
}

Here is the model.go file

package model
//go:generate codecgen -o codec_gen.go model.go

type Test struct {
    Key string `json:"_key,omitempty"`
}

type Next struct {
    Test
    Field1 string `json:"_id,omitempty"`
    Field2 string `json:",omitempty"`
}

[ugorji]

The only problem is with the codec-generated one from what i see.

i.e. codec generated one doesn't take the struct tags into account.

Is that correct?

If so, can you ensure that you have the latest version of codecgen? Do a 'go get -u github.com/ugorji/go/codec/codecgen github.com/ugorji/go/codec'

[ugorji]

i.e. if you do a

t.Key="whynot"

Then you will see that both runtime-introspection (reflection) modes work the same. The only discrepancy is in the generated code, as it looks like it does honor the struct tags. I believe this was fixed a while back, which is why I want you to try and re-update, to see if the issue currently exists, before i look deeper.

Thanks much.

[starJammer]

Hey Ugorij,
Thanks for responding. I downloaded the code this morning with the -u option so I doubt that is the issue. Today was also the first time I ran go get. I'll update the code again anyway using the command you gave me just to be safe.

Yes, you're right. Only 1 issue. I didn't set the Key field of the second struct I was testing.

With the codec generated code:

1. Yes, the struct tags aren't taken into account. Specifically, they are using the struct field names instead

[starJammer]

I ran the following commands

1. rm codecgen in the bin directory where it was installed. In my $GO_BIN
2. go get -u github.com/ugorji/go/codec/codecgen github.com/ugorji/go/codec
3. codecgen -o codec_gen.go model.go to regenerate the generated code.
4. go build main.go in root to build
5. ./main to run the program.

I still received incorrect output for the generated code. The reflection based code came out correct though. I updated my original post to reflect this.

[ugorji]

@starJammer Please try now with updates and let me kow that it works.

Thanks.

[starJammer]

I think things are worse now. The codecgen command is spitting out an error and two very small files are being generated when I use the -x option.

Command I ran: codecgen -x=true -o=codec_gen.go model.go

codecgen error: Error running go run codecgen-main-1429668731680257800.generated.go. Error: exit status 2. stdout/err: # command-line-arguments
./codecgen-main-1429668731680257800.generated.go:6: undefined: model.CodecGenTempWrite1429668731680257800

The codecgen-main-1429668731680257800.generated.go file

//+build ignore

package main
import "bitbucket.org/starJammer/tester/model"
func main() {
    model.CodecGenTempWrite1429668731680257800()
}

The codecgen-pkg-1429668731680257800.generated.go file

//+build codecgen

package model

import (
    codec1978 "github.com/ugorji/go/codec"

    "os"
    "reflect"
    "bytes"
    "go/format"
)



func CodecGenTempWrite1429668731680257800() {
    fout, err := os.Create("codec_gen.go")
    if err != nil {
        panic(err)
    }
    defer fout.Close()
    var out bytes.Buffer

    var typs []reflect.Type 

    var t0 Test
    typs = append(typs, reflect.TypeOf(t0))

    var t1 Next
    typs = append(typs, reflect.TypeOf(t1))

    codec1978.Gen(&out, "", "model", false, typs...)
    bout, err := format.Source(out.Bytes())
    if err != nil {
        fout.Write(out.Bytes())
        panic(err)
    }
    fout.Write(bout)
}

[ugorji]

The codecgen-pkg-1429668731680257800.generated.go should not have had the //+build codecgen,
as that would require that each call to codecgen passes the '-rt codecgen' option.

This should be resolved now.

Please retry.

Thanks.

[starJammer]

The resolves it. Thank you for the amazing support.

Encodings from codec generated selfer code....
{"_key":"thing"}
{"_key":"whynot","_id":"another"}
Encodings from codec reflection based encoding....
{"_key":"thing"}
{"_id":"another","_key":"whynot"}
Encodings from encoding/json....
{"_key":"thing"}
{"_key":"whynot","_id":"another"}