3.0.2: --- thematic break inside an MDC block is parsed as YAML props (render errors / silently dropped content)

[HermessNRJ]

Summary

Inside an MDC block component (for example ::block-tab), a line containing only --- is treated as the opening of a YAML props section when it starts a block. Everything up to the next --- is parsed as YAML. In standard Markdown, and in Wiki.js 2.x, --- on its own line after a blank line or a list is a thematic break (<hr>).

This has two effects:

• Render failure when the text between two --- lines is not valid YAML.
• Silent content loss when the text happens to be valid YAML (for example key : value lines). It is consumed as props and never displayed.

It affects pages imported from 2.x. Using --- as a separator between sections is very common there, and it ends up inside block-tabs once tabsets are converted.

Environment

• Wiki.js 3.0.2 (Helm chart wiki 3.0.2)
• Pages imported from a Wiki.js 2.5.317 .wkbackup

Minimal reproduction

:::block-tabs
::block-tab{label="Tab 1"}
**Resolutions**

---
- **Conditions : Public/Public**
- Verdict : True Positive
---
- **Conditions : Public/Private**
- Verdict : True Positive
::
:::

Observed

Render errors seen in the server log for imported pages:

error: Failed to render page <id> (<path>): Unresolved alias (the anchor must be set before the alias): *Conditions
error: Failed to render page <id> (<path>): YAMLParseError: Unexpected scalar at node end at line 6, column 1:
error: Failed to render page <id> (<path>): YAMLParseError: Implicit keys need to be on a single line at line 2, column 1:
error: Failed to render page <id> (<path>): YAMLParseError: Not a YAML token: ... at line 4, column 3:

8 pages out of about 3000 failed this way. A scan of the package found about 1900 --- thematic breaks in positions where the same thing can happen, so other pages likely lost content without any error.

Expected

A --- that is not right after the component's opening line should render as <hr>, as in CommonMark and in 2.x. YAML props should only be recognised immediately after ::component-name (the MDC spec form):

::block-tab
---
label: Tab 1
---
content
::

Alternatively, the 2.x importer could rewrite such thematic breaks to ***, which renders the same and is never read as YAML.

Workaround

Before importing, we replace standalone --- lines that start a block (outside code fences) with ***. A --- directly under a paragraph line is left alone, because that is a setext heading. With this change, all affected pages render.

[NGPixel]

Fixed via 00b8271. Will land in next release.