Cursor Does Not Move to Next Snippet Placeholder Position When Accepting a Completion Within a Snippet Placeholder Node

[Drew-Daniels]

I noticed an issue when using snippets, like the one I have for .json files:

{
  "Property": {
    "body": "\"${1:KEY}\": ${2:VALUE}",
    "prefix": "pr",
    "description": "A JSON Object Property"
  }
}

If I am typing within the first snippet node, and see a completion come up that I would like to use, like language, if I accept that completion, I exit the snippet, and can't jump to the next node of the snippet.

Instead of this, I would expect for me to jump to the next node, like this:

[Saghen]

I can't handle all cases since accepting a snippet completion item (which can be returned by any source, not just the snippet source) will call vim.snippet.expand which replaces the current snippet context. However, the buffer source was incorrectly marking its items as snippets which caused the issue for this specific case