Parsing YAML files with anchors does not keep pointers to anchors when unmarshalling

[timgws]

Thanks @goccy for your work on this package :)

Similar to #69, I have a configuration file that looks like this:

hosts:
  - host: &host1
      hostname: queue.example.com
      username: queue1
      password: queue1
      port: 5672

  - host: &host2
      hostname: queue2.example.com
      username: queue2
      password: queue2
      port: 5672

queues:
  - name: queue
    host: *host1
  - name: queue2
    host: *host1
  - name: queue3
    host: *host2

I have a set of structs in a separate package, describing the YAML file

package configuration

type HostList struct {
	Host *Host  `yaml:",inline,anchor"`
	Name string `yaml:","`
}

type Host struct {
	*Host    `yaml:",omitempty"`
	Hostname string
	Username string
	Password string
}

type Queue struct {
	Name  string `yaml:","`
	*Host `yaml:",alias"`
}

type ConfigFile struct {
	HostList []*HostList `yaml:"hosts"`
	Queues   []*Queue    `yaml:"queues"`
}

I am reading my configuration file like this

func Read(configFile string) (error, ConfigFile) {
	var cf ConfigFile
	yamlFile, err := ioutil.ReadFile(configFile)
	if err != nil {
		return err, cf
	}

	err = yaml.Unmarshal(yamlFile, &cf)
	if err != nil {
		// clear the config file that might have been partially parsed
		var cf ConfigFile
		return err, cf
	}

	return nil, cf
}

and inside my main.go, I have the following code:

	err, cf = configuration.Read(configFile)
	if err != nil {
		log.Fatal(err)
		return err
	}

	fmt.Println(Configuration.Queues[0].Host.Hostname)
	fmt.Println(Configuration.Queues[1].Host.Hostname)

	Configuration.Queues[0].Host.Hostname = "updated_hostname.example.org"
	
	fmt.Println(Configuration.Queues[0].Host.Hostname)
	fmt.Println(Configuration.Queues[1].Host.Hostname)

Expected output:

queue.example.com
queue.example.com
updated_hostname.example.org
updated_hostname.example.org

Actual output:

queue.example.com
queue.example.com
updated_hostname.example.org
queue.example.com

It seems that the anchor in the created document to host1 is not being respected when unmarshalling the document.

I would expect that both Configuration.Queues[0].Host and Configuration.Queues[1].Host would be a pointer to Configuration.Hosts[0].Host, reflecting the document's intent.

[goccy]

@timgws

I fixed with #72 and released as v1.2.0 !
If you like this library, I'd be happy if you could promote this around .

Thanks

[timgws]

I fixed with #72 and released as v1.2.0 !

I just tested this with the above code, and it does not work. Configuration.HostList[0] and Configuration.HostList[1] are both empty.

The Actual output remains the same as the previous commit.

[goccy]

@timgws

The above code is wrong, it does not work .
( HostList and Host definition is wrong )

The following code works fine .

package main

import (
	"github.com/goccy/go-yaml"
)

type Host struct {
	Hostname string
	Username string
	Password string
}

type HostList struct {
	Host *Host `yaml:",anchor"`
}

type Queue struct {
	Name  string `yaml:","`
	*Host `yaml:",alias"`
}

type ConfigFile struct {
	HostList []*HostList `yaml:"hosts"`
	Queues   []*Queue    `yaml:"queues"`
}

func main() {
	yml := `
hosts:
  - host: &host1
      hostname: queue.example.com
      username: queue1
      password: queue1
      port: 5672

  - host: &host2
      hostname: queue2.example.com
      username: queue2
      password: queue2
      port: 5672

queues:
  - name: queue
    host: *host1
  - name: queue2
    host: *host1
  - name: queue3
    host: *host2
`

	var cf ConfigFile
	if err := yaml.Unmarshal([]byte(yml), &cf); err != nil {
		panic(err)
	}
	cf.Queues[0].Host.Hostname = "updated"
}

[timgws]

Ah! It happened when HostList had inline inside the Host yaml parameters.

Thanks so much for all your help here @goccy

I will try over the next couple of days to get goccy/go-yaml to marshel files in the same format that was unmarshaled.

Words can't explain how much I appreciate the last two commits :)