omitempty not working for int/float

[coanor]

Related to #221

For tag version v0.3.1

 package main

 import (
   "bytes"
   "log"

   "github.com/BurntSushi/toml"
 )

 func demo0() {
   type X struct {
     Int int     `toml:"int,omitempty"`
     Str string  `toml:"str,omitempty"`
     F64 float64 `toml:"f64,omitempty"`
     I64  int64   `toml:"i64,omitempty"`
     U64  uint64  `toml:"u64,omitempty"`
   }

   x := X{Str: ""}

   var buf bytes.Buffer

   if err := toml.NewEncoder(&buf).Encode(x); err != nil {
     log.Fatal(err)
   }

   log.Printf("\n%s", buf.String())
 }

 func main() {
   demo0()
 }

the output is

2021/08/01 13:12:06
int = 0
f64 = 0.0
i64 = 0
u64 = 0

It seems that, the omitempty not working on int and float.

[arp242]

You need to use omitzero, not omitempty. The way it works:

• omitempty – Don't write if the value is "empty": len(0) for arrays, slices, maps, strings, false for bools

• omitzero – Don't write if the value is zero, only works for numbers.

It's annoying that it works like this, but there isn't any way to change this to the more standard behaviour without breaking comparability. It's one of the things that will be fixed in a hypothetical unplanned v2 release. See: #120.