User tag in yaml frontmatter breaks preview

Please select the area your bug applies to.

[ ] Workspace. VSCode workspace, vaults, Intellisense/autocomplete, Dendron settings
[ ] Lookup. Dendron's Lookup Command
[x] Views. Dendron Preview, Tree View, Side Panels in the UI
[ ] Schema. Dendron Schemas
[ ] Publish. External Site Publish
[ ] Pod. Data import from / export to Dendron
[ ] Markdown. Markdown features, such as syntax support and features

Describe the bug

User tag in yaml frontmatter breaks preview. Adding a user tag will freeze the preview if its already open, or the preview will lock in buffering if you try to launch it.

Backlinks appear to work normally though.

To Reproduce

MWE:

---
id: oeisf4b85cnljmho66kk8fq
title: Paper title
desc: 'Reading notes'
updated: 1664485041841
created: 1664479886525
PaperAuthors:
  - @Ana
  - Bob
  - Carl
---

Lorem ipsum

Desktop (please complete the following information)

OS: Linux
Versions (all that apply to bug):
- Dendron Extension: v0.114.0
- VS Code version: 1.72.0-insider
- Dendron CLI:

Additional context

I wanted to push some user mentions to the yaml frontmatter so that the notes are linked, but I don't necessarily need this linking to occupy the text body. This, however, breaks the preview. It may not be a big deal on its own, but it may be a symptom of a limitation in the frontmatter parsing by Dendron.

If this is by design, is it documented anywhere? I couldn't find it.

Thank you for the report.

Apologies for the confusion. This is an issue we are aware of internally but is not documented well for the public.

The issue arises due to the fact that yaml (frontmatter) does not allow the special symbol @ in plain values. Unfortunately bending the rules of the yaml specification and writing a custom parser for this is a bit involved.

If this is by design, is it documented anywhere? I couldn't find it.

It is not by design. I would say that the limitation in the yaml specification / the use of user tags in frontmatter was not under our radar when we decided @ is the syntax for user tags.

For the time being, the only way to use the @ syntax is to wrap everything in a quote which makes user tags pointless. You can instead opt not to user the user tag syntax and use wikilinks in frontmatter, which works as expected.

We'll discuss how this should be handled and let you know when we make any progress on this matter.

dendronhq / dendron