codecgen: missing field with nested omitEmpty struct

[vanackere]

Hi, I hope this bug is not a user error this time ;-)

I have a test case failing with the current codecgen (the same code was working before updating the package). Minimal reproduction:

// file: user.go
package testcodec

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

type S struct {
	A string
	B string
}

type User struct {
	MaybeEmpty S `json:",omitempty"`
}

func toJSON(u *User) ([]byte, error) {
	var res []byte
	h := &codec.JsonHandle{}
	enc := codec.NewEncoderBytes(&res, h)
	err := enc.Encode(u)
	return res, err
}

The following test passes without codecgen and fails with code generation for the User type (codecgen -d 1977 -o user_codecgen.go -r User user.go):

// file: user_test.go
package testcodec

import (
	"testing"

	"github.com/stretchr/testify/assert"
)

func TestToJSON(t *testing.T) {
	r, _ := toJSON(&User{
		MaybeEmpty: S{
			A: "a",
		},
	})
	assert.Equal(t, `{"MaybeEmpty":{"A":"a","B":""}}`, string(r))
	// With codecgen:
	//--- FAIL: TestToJSON (0.00s)
	//    user_test.go:15: 
	//                Error Trace:    user_test.go:15
	//                Error:          Not equal: 
	//                                expected: "{\"MaybeEmpty\":{\"A\":\"a\",\"B\":\"\"}}"
	//                                actual  : "{}"
}

[ugorji]

This looks like a real bug.

Let me look into it this weekend.

[ugorji]

BTW, can you run it without RecursiveEmptyCheck and post what you see? Thanks.

[vanackere]

Mhh I see the same bug without RecursiveEmptyCheck:

--- FAIL: TestToJSON (0.00s)
    user_test.go:16: 
                Error Trace:    user_test.go:16
                Error:          Not equal: 
                                expected: "{\"ID\":12,\"MaybeEmpty\":{\"A\":\"a\",\"B\":\"\"}}"
                                actual  : "{\"ID\":12}"
                            
                                Diff:
                                --- Expected
                                +++ Actual
                                @@ -1 +1 @@
                                -{"ID":12,"MaybeEmpty":{"A":"a","B":""}}
                                +{"ID":12}
                Test:           TestToJSON

[vanackere]

I updated the title and made the bug reproduction code shorter (it turns out that the ID field was not necessary either)

[vanackere]

Here is the generated file in case it helps:

// +build go1.6

// Code generated by codecgen - DO NOT EDIT.

package testcodec

import (
	"errors"
	"runtime"
	"strconv"

	codec1978 "github.com/ugorji/go/codec"
)

const (
	// ----- content types ----
	codecSelferCcUTF81977 = 1
	codecSelferCcRAW1977  = 255
	// ----- value types used ----
	codecSelferValueTypeArray1977     = 10
	codecSelferValueTypeMap1977       = 9
	codecSelferValueTypeString1977    = 6
	codecSelferValueTypeInt1977       = 2
	codecSelferValueTypeUint1977      = 3
	codecSelferValueTypeFloat1977     = 4
	codecSelferValueTypeNil1977       = 1
	codecSelferBitsize1977            = uint8(32 << (^uint(0) >> 63))
	codecSelferDecContainerLenNil1977 = -2147483648
)

var (
	errCodecSelferOnlyMapOrArrayEncodeToStruct1977 = errors.New(`only encoded map or array can be decoded into a struct`)
)

type codecSelfer1977 struct{}

func codecSelfer1977False() bool { return false }
func codecSelfer1977True() bool  { return true }

func init() {
	if codec1978.GenVersion != 20 {
		_, file, _, _ := runtime.Caller(0)
		ver := strconv.FormatInt(int64(codec1978.GenVersion), 10)
		panic(errors.New("codecgen version mismatch: current: 20, need " + ver + ". Re-generate file: " + file))
	}
}

func (x *User) CodecEncodeSelf(e *codec1978.Encoder) {
	var h codecSelfer1977
	z, r := codec1978.GenHelper().Encoder(e)
	_, _, _ = h, z, r
	if x == nil {
		r.EncodeNil()
	} else {
		yy2arr2 := z.EncBasicHandle().StructToArray
		_ = yy2arr2
		const yyr2 bool = false // struct tag has 'toArray'
		var yyq2 = [1]bool{     // should field at this index be written?
			!(x.MaybeEmpty.IsCodecEmpty()), // MaybeEmpty
		}
		_ = yyq2
		if yyr2 || yy2arr2 {
			z.EncWriteArrayStart(1)
			z.EncWriteArrayElem()
			if yyq2[0] {
				yy4 := &x.MaybeEmpty
				if yyxt5 := z.Extension(yy4); yyxt5 != nil {
					z.EncExtension(yy4, yyxt5)
				} else {
					z.EncFallback(yy4)
				}
			} else {
				r.EncodeNil()
			}
			z.EncWriteArrayEnd()
		} else {
			var yynn2 int
			for _, b := range yyq2 {
				if b {
					yynn2++
				}
			}
			z.EncWriteMapStart(yynn2)
			yynn2 = 0
			if yyq2[0] {
				z.EncWriteMapElemKey()
				if z.IsJSONHandle() {
					z.WriteStr("\"MaybeEmpty\"")
				} else {
					r.EncodeString(`MaybeEmpty`)
				}
				z.EncWriteMapElemValue()
				yy6 := &x.MaybeEmpty
				if yyxt7 := z.Extension(yy6); yyxt7 != nil {
					z.EncExtension(yy6, yyxt7)
				} else {
					z.EncFallback(yy6)
				}
			}
			z.EncWriteMapEnd()
		}
	}
}

func (x *User) CodecDecodeSelf(d *codec1978.Decoder) {
	var h codecSelfer1977
	z, r := codec1978.GenHelper().Decoder(d)
	_, _, _ = h, z, r
	yyct2 := r.ContainerType()
	if yyct2 == codecSelferValueTypeNil1977 {
		*(x) = User{}
	} else if yyct2 == codecSelferValueTypeMap1977 {
		yyl2 := z.DecReadMapStart()
		if yyl2 == 0 {
		} else {
			x.codecDecodeSelfFromMap(yyl2, d)
		}
		z.DecReadMapEnd()
	} else if yyct2 == codecSelferValueTypeArray1977 {
		yyl2 := z.DecReadArrayStart()
		if yyl2 != 0 {
			x.codecDecodeSelfFromArray(yyl2, d)
		}
		z.DecReadArrayEnd()
	} else {
		panic(errCodecSelferOnlyMapOrArrayEncodeToStruct1977)
	}
}

func (x *User) codecDecodeSelfFromMap(l int, d *codec1978.Decoder) {
	var h codecSelfer1977
	z, r := codec1978.GenHelper().Decoder(d)
	_, _, _ = h, z, r
	var yyhl3 bool = l >= 0
	for yyj3 := 0; ; yyj3++ {
		if yyhl3 {
			if yyj3 >= l {
				break
			}
		} else {
			if z.DecCheckBreak() {
				break
			}
		}
		z.DecReadMapElemKey()
		yys3 := z.StringView(r.DecodeStringAsBytes())
		z.DecReadMapElemValue()
		switch yys3 {
		case "MaybeEmpty":
			if yyxt5 := z.Extension(x.MaybeEmpty); yyxt5 != nil {
				z.DecExtension(&x.MaybeEmpty, yyxt5)
			} else {
				z.DecFallback(&x.MaybeEmpty, false)
			}
		default:
			z.DecStructFieldNotFound(-1, yys3)
		} // end switch yys3
	} // end for yyj3
}

func (x *User) codecDecodeSelfFromArray(l int, d *codec1978.Decoder) {
	var h codecSelfer1977
	z, r := codec1978.GenHelper().Decoder(d)
	_, _, _ = h, z, r
	var yyj6 int
	var yyb6 bool
	var yyhl6 bool = l >= 0
	yyj6++
	if yyhl6 {
		yyb6 = yyj6 > l
	} else {
		yyb6 = z.DecCheckBreak()
	}
	if yyb6 {
		z.DecReadArrayEnd()
		return
	}
	z.DecReadArrayElem()
	if yyxt8 := z.Extension(x.MaybeEmpty); yyxt8 != nil {
		z.DecExtension(&x.MaybeEmpty, yyxt8)
	} else {
		z.DecFallback(&x.MaybeEmpty, false)
	}
	for {
		yyj6++
		if yyhl6 {
			yyb6 = yyj6 > l
		} else {
			yyb6 = z.DecCheckBreak()
		}
		if yyb6 {
			break
		}
		z.DecReadArrayElem()
		z.DecStructFieldNotFound(yyj6-1, "")
	}
}

func (x *User) IsCodecEmpty() bool {
	return !(!(x.MaybeEmpty.IsCodecEmpty()) && true)
}

func (x *S) IsCodecEmpty() bool {
	return !(x.A != "" && x.B != "" && true)
}

[vanackere]

I sent a pull request that should fix this issue, please merge ASAP if correct, this is a serious issue I think

[myusuf3]

Would be great to get this in.