Block Metadata Not Supported
Q-3-20 — Block Metadata Not Supported
YAML metadata blocks are internal AST nodes that cannot be rendered in this output format.
What this means
Quarto represents document-level YAML (the --- front matter)
and block-level metadata fences as their own AST node type. The
render pipeline normally consumes these nodes before they reach
the writer — front matter becomes document metadata, block
metadata is attached to the block it annotates, and the
metadata-as-node form disappears.
This error fires when a BlockMetadata node survives to the
writer. The writer has nowhere to put it: it is structurally a
block, but its content is YAML, not prose.
Why this happens
Most often a Lua filter, or another non-default processing path, left a metadata block in the AST when it should have consumed or attached it. The error is defensive — the normal pipeline does not produce this shape.
How to fix
Identify the filter or processing step that introduced the
orphan metadata. If a filter is creating BlockMetadata nodes
deliberately, either consume them within the filter or rewrite
them into a representation the writer can render (a RawBlock,
for example).
If no custom filter is in use, report the document at the Quarto issue tracker — the pipeline should not leave block metadata behind.