Inconsistent comments handling for empty nodes

[roman-burdeiniy]

Describe the bug
Inconsistent behaviour of parseDocument function.
Once yaml contains deep hierarchical of empty nodes the comment from the next node on a top level is getting ignored. Instead it appears on a wrong level of hierarchy. See example below.

To Reproduce
Consider yaml

SettingsMenuPopup:

  #@desc: Colours for settings button by modes.
  iconColor:
    open:

  #@desc: Settings button configuration.
  #@class: Button
  button:

Use const document = yaml.parseDocument(fileSource, { sortMapEntries: true });

Expected behaviour
The comment "@desc: Settings button configuration.\n@class: Button" should be on "button" Scalar on level:
document.contents.items[0].value.items[1].value.comment.

Actual behaviour
The comment "@desc: Settings button configuration.\n@class: Button" appears on "iconColor.open" level Scalar:
document.contents.items[0].value.items[0].value.items[0].value.comment.

Versions (please complete the following information):

• Environment: [e.g. Node.js 14.7.0 or Chrome 87.0]
  Node v20.0.0
• yaml: [e.g. 1.10.0 or 2.0.0-2]
  2.3.1
  According to my local tests the bug was introduced in 2.0.0-4

Additional context
The issue will be solved if I explicitly apply null to empty node in yaml, e.g.

SettingsMenuPopup:

  #@desc: Colours for settings button by modes.
  iconColor:
    open: null

  #@desc: Settings button configuration.
  #@class: Button
  button:

[eemeli]

This is pretty much the same as #490. As I mention there:

YAML does not specify how comments are attached, and as you see here, there isn't always just one way to attach a comment. You're welcome to suggest changes in the logic for comment attachment, but you'll probably need to submit a PR yourself. Be warned, though, the heuristics on this can get a bit hairy as it's pretty much all corner cases.

[roman-burdeiniy]

yeah, thanks for answering and seems it is the same issue as 490 as you said. The comments in yaml can be practically anywhere and they are not bound in any way to the scalar except visually.
But yaml lib actually tries to do this and I found this super useful in our project use cases (we probably should not relay on comments in our build process though, but unfortunately not possible to get rid of this now). Anyways my point is that in order to keep parsing comments per node yaml lib should define strict rules of attaching a comment. Other "free style comments" could be ignored. Scanning for a comment all around and trying to guess to what it belongs to will probably never be completely reliable.

[eemeli]

I would reiterate that you're welcome to suggest changes in the logic for comment attachment, but you'll probably need to submit a PR yourself.

[roman-burdeiniy]

I see, thank you for opportunity to contribute. But unfortunately I'm not able to work on third party projects right now. What I wanted to figure out is if this is considered as a bug and if yes then if it is planned to be fixed by active contributors. Otherwise we would probably just revert to previous stable version as of now