At "sigs.k8s.io/yaml/goyaml.v2", marshal output is incorrect when the string field is long and contains Colon and Space(: )

[koba1t]

What happened?

The marshal output is incorrect when the string field is long and contains Colon and Space(: ) at "sigs.k8s.io/yaml/goyaml.v2" pkg.

How can we reproduce it (as minimally and precisely as possible)?

code

https://go.dev/play/p/WDmfH-PWqtW

package main

import (
	"fmt"
	"log"

	yaml "sigs.k8s.io/yaml/goyaml.v2"
)

type StructA struct {
	A string `yaml:"a"`
}

var data = `
a: "12345678901234: .s"
`

var failedData = `
a: "12345678901234567890123456789012345678901234567890123456789012341234567890123456789012345678901234567890123456789012345678901234: .s"
`

func processYAML(input string) {
	var a StructA
	if err := yaml.Unmarshal([]byte(input), &a); err != nil {
		log.Printf("cannot unmarshal data: %v", err)
		return
	}

	yamlBytes, err := yaml.Marshal(a)
	if err != nil {
		log.Printf("cannot marshal data: %v", err)
		return
	}

	fmt.Println(string(yamlBytes))
}

func main() {
	processYAML(data)
	processYAML(failedData)
}

output

a: '12345678901234: .s'

a: '12345678901234567890123456789012345678901234567890123456789012341234567890123456789012345678901234567890123456789012345678901234:
  .s'

Additionally

related to kubernetes-sigs/kustomize#947

[liggitt]

it's not clear to me that the resulting yaml is invalid... it round-trips correctly when unmarshaled (see https://go.dev/play/p/_v1ZSI-MnM3), and other yaml linters (e.g. https://www.yamllint.com/, https://yaml-online-parser.appspot.com/) validate it and appear to interpret it correctly

[koba1t]

Sorry, I didn't know about 'line folding' in the YAML specification.
https://yaml.org/spec/1.2.2/#65-line-folding

I mistakenly thought it looked like an unexpected extra line break had been added.

a: '12345678901234567890123456789012345678901234567890123456789012341234567890123456789012345678901234567890123456789012345678901234:
  .s'

/close

[k8s-ci-robot]

@koba1t: Closing this issue.

In response to this:

Sorry, I didn't know about 'line folding' in the YAML specification.
https://yaml.org/spec/1.2.2/#65-line-folding

I mistakenly thought it looked like an unexpected extra line break had been added.

a: '12345678901234567890123456789012345678901234567890123456789012341234567890123456789012345678901234567890123456789012345678901234:
 .s'

/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[r10r]

@liggitt Do you mind to reopen this issue ?

I'm facing the same issue and according to go-yaml/yaml#455 (comment)
folding should already have been disabled in goyaml.v2. But it has not.

The YAML output becomes difficult to read and edit due to the line wrapping.
So it should be at least possible to disable the line wrapping in the encoder.
This should be fairly easy looking at the following pull requests:

• Revert "Set the default line length to infinity (-1) (#571)" go-yaml/yaml#670
• Feature (v3): Add a function to set the desired line length of an Encoder go-yaml/yaml#455
• Add method to set preferred line width. go-yaml/yaml#329

What about merging go-yaml/yaml#329 into the fork of goyaml.v2 ?

[liggitt]

We won't reopen this specific issue, since the output is not actually incorrect.

Given that changing the line wrapping default in go-yaml broke things, and they had to back that change out, I'm not inclined to import that problem to this repo. More configurability / options in yaml output wouldn't help users of things like kubectl / kustomize, which would continue to keep compatible defaults using current wrapping behavior.

[r10r]

Thanks for the explanation. I think about creating a fork, but I wonder if this is a good idea. Do you know what exactly breaks when the maximum line width is changed? I'm fine with increasing the maximum line to a fixed width, let's say 200 chars. Will this generate invalid yaml ?

[liggitt]

Do you know what exactly breaks when the maximum line width is changed?

For kubectl / kustomize users, anything expecting stable (byte-equivalent) output in yaml format release-to-release. It's still semantically equal, but was not byte-equal