I have a question about the semantics of child_count in the comment list API endpoint. Sorry for being related to an earlier question but I haven't quite figured it out yet.

My assumption was that child_count would indicate the amount of total descendants of a comment, regardless of depth. But take this case for example:

$ curl 'https://lemmy.ml/api/v3/comment/list?parent_id=2157873&max_depth=999&limit=999' | jq '.comments[]
| { path: .comment.path, id: .comment.id, content: .comment.content, child_count: .counts.child_count }'
{
  "path": "0.2157873",
  "id": 2157873,
  "content": "Really cool! I'm excited to learn more about you and the project!\n\nWhat's the format? Should we submit questions beforehand, or will you process questions that arrive at the start time? I've never participated in an AMA  😅 ",
  "child_count": 9
}
{
  "path": "0.2157873.2158260",
  "id": 2158260,
  "content": "You just post questions as top-level replies to the stickied thread that day, and we'll be online to answer them.",
  "child_count": 6
}
{
  "path": "0.2157873.2158260.2158286",
  "id": 2158286,
  "content": "Cool. Thank you for doing this!",
  "child_count": 1
}
{
  "path": "0.2157873.2158260.2229041",
  "id": 2229041,
  "content": "Post doesn’t mention, where is the AMA? Here or in a different community?",
  "child_count": 3
}
{
  "path": "0.2157873.2158260.2158286.2158743",
  "id": 2158743,
  "content": "No probs!",
  "child_count": 0
}
{
  "path": "0.2157873.2158260.2229041.2231423",
  "id": 2231423,
  "content": "As the post mentions, it will be stickied to the top of lemmy.ml ",
  "child_count": 2
}
{
  "path": "0.2157873.2158260.2229041.2231423.2231737",
  "id": 2231737,
  "content": "Thanks for the details. May be I’m missing something, but I don’t see that detail in the post. ![](https://programming.dev/pictrs/image/82c90859-9cfb-4c00-80d8-7e96bfd96c1c.jpeg)",
  "child_count": 1
}
{
  "path": "0.2157873.2158260.2229041.2231423.2231737.2238347",
  "id": 2238347,
  "content": "Oops my bad, that was something I responded to in a comment.",
  "child_count": 0
}

I see that comment 2157873 has a child count of 9, with one direct descendant (2158260). The descendant has a child count of 6. I'd reason that comment 2157873 has 2 direct descendants that aren't visible in the API response yet, because it has one visible descendant having a child count of 6 (i.e. 9 - 1 - 6 = 2). My calculation seems incorrect because (a) I don't see a 'Load more' indicator for this part of the comment thread on https://lemmy.ml/post/2671212, and (b) every comment shown there also seems present in the API response.

Am I understanding the meaning of child_count correctly?

  • RoundSparrow@lemmy.ml
    ·
    edit-2
    11 months ago

    I have this post replicated to my own instance where I have direct SQL access: https://BulletinTree.com/comment/1318138

    Show

    I'm looking at it and I see 2 deleted-by-creator that seem to be direct replies to the first comment in the branch that says 9.

    The lemmy-ui I am running is off main, not the 0.18.0 branch, and I just updated it a couple days ago. But it obviously differs in exposing these, and so does my API.

    EDIT: I updated my lemmy-ui to main just now again, it had changes, and still showing. Obviously my API is returning the deleted comments for not-logged-in users still... I wonder if that's because I'm running main of lemmy_server and not the 0.18.4 tag branch and they differ in behavior.

    • FrostySpectacles@lemmy.ml
      hexagon
      ·
      11 months ago

      Interesting! If there are two deleted comments underneath 2157873, that could indeed explain the two "missing" comments.

    • FrostySpectacles@lemmy.ml
      hexagon
      ·
      edit-2
      11 months ago

      I took a look at how the official Lemmy UI uses child_count, and it appears to use the number verbatim in its "X more replies" link. So if a comment tree were to include deleted comments, but child_count includes the deleted ones, I'd assume the displayed number would be incorrect.

      Also, it appears that it only displays a load more link if no child comments are currently loaded for that comment and child_count is bigger than 0.