missing comments in yaml encoder

[sahroshan]

What version of CUE are you using (cue version)?

$ cue version
v0.5.0

Does this issue reproduce with the latest stable release?

yes

What did you do?

package main

import (
	"fmt"

	"cuelang.org/go/cue"
	"cuelang.org/go/cue/cuecontext"
	"cuelang.org/go/encoding/yaml"
)

const val = `
// will it appear in yaml
i: int | *123
`

func main() {
	var (
		c *cue.Context
		v cue.Value
	)

	// create a context
	c = cuecontext.New()

	// compile some CUE into a Value
	v = c.CompileString(val)
	yamlSkeleton, _ := yaml.Encode(v)
	fmt.Println(string(yamlSkeleton))
}

What did you expect to see?

# will it appear in yaml
i: 123

What did you see instead?

i: 123

I tried debugging the issue. Below are my findings.

we are converting converting cue.Value to ast.Node at

cue/encoding/yaml/yaml.go

Line 84 in d780488

n := v.Syntax(cue.Final())

.

The ast.Node supports comment

cue/cue/types.go

Line 984 in d780488

ShowDocs: o.docs,

.

below changes fixes the issue.

FROM:

cue/encoding/yaml/yaml.go

Line 84 in d780488

n := v.Syntax(cue.Final())

TO:

n := v.Syntax(cue.Final(), cue.Docs(true))

[mvdan]

I believe this is a duplicate of #1180 :)

[mvdan]

Closing for now.