Pfthb

Given the following YAML:

array.test: ["val1", "val2", "val3"]

I Unmarshal it using gopkg.in/yaml.v2 into a map[string]interface. Then I get a single key whose value is an array of 3 values.

When I then Marshal it again to YAML, the resulting YAML looks like this:

array.test:
- val1
- val2
- val3

The array was actually marshaled as a sequence instead of an array.

This is the entire GoLang code:

func main()
 data := `array.test: ["val1", "val2", "val3"]`
 conf := make(map[string]interface)
 yaml.Unmarshal(byte(data), conf)

 data2, _ := yaml.Marshal(conf)
 fmt.Printf("%sn", string(data2))

How can I overcome this issue?

This one helped me in the same case as you.

package main

import (
 "fmt"
 "log"

 "gopkg.in/yaml.v2"
)

var data = `
a: Easy!
b:
c: 2
d.test: ["d1", "d2"]
`

// Note: struct fields must be public in order for unmarshal to
// correctly populate the data.
type T struct 
 A string
 B struct 
 RenamedC int `yaml:"c"`
 DTest string `yaml:"d.test,flow"`
 


func main() 
 // if we use struct containing yaml encoding for yaml formated string 
 t := T

 err := yaml.Unmarshal(byte(data), &t)
 if err != nil 
 log.Fatalf("error: %v", err)
 
 fmt.Printf("--- t after unmarshal:n%vnn", t)

 d, err := yaml.Marshal(&t)
 if err != nil 
 log.Fatalf("error: %v", err)
 
 fmt.Printf("--- t after marshal:n%snn", string(d))

Ref: https://github.com/go-yaml/yaml

Use flow in struct field tag format, to indicate you desire this behavior. But, of course, this requires unmarshaling to a struct, not to a map.

Flow tag allows you to choose the representation of an array in yaml

package main

import (
 "fmt"
 "gopkg.in/yaml.v2"
)

type Conf struct 
 Test string `yaml:"array.test,flow"`


func main()
 data := `array.test: ["val1", "val2", "val3"]`
 var conf Conf
 yaml.Unmarshal(byte(data), &conf)

 data2, _ := yaml.Marshal(conf)
 fmt.Printf("%sn", string(data2))