Shouldn't in-document metadata override defaults file metadata?

[bpj]

In a defaults file
$PANDOC_DATA_DIR/defaults/lualatex.yaml I have

metadata:
  mainfont: Noto Serif
  sansfont: Noto Sans
  monofont: Noto Sans Mono

In the metadata block of my Markdown file I have:

mainfont: Charis SIL

The generated LaTeX has Noto Serif as mainfont which is
not what I expect, as I thought that the metadata in
the Markdown file should have higher priority.

I can work around this by creating a file charis.yaml containing just

metadata:
  mainfont: Charis SIL

and using the commandline

pandoc -d lualatex.yaml -d charis.yaml -o mydoc.pdf mydoc.md

but should it really be necessary?

pandoc 3.6.4

[jgm]

I thought that the metadata in the Markdown file should have higher priority.

Is that suggested by something in the documentation?

Here is a way to think of defaults files. They specify default values for things that can be specified by options on the command line, and they behave as if you had put these things on the command line. Since a --metadata on the command line would override what you have in your document, the same is true for a defaults file.

You can probably achieve your purpose by putting these things in a YAML metadata file that you call with --metadata-file. (Drop the metadata: key for that.)

You could even put

metadata-file: your-standard-metadata.yaml

in your defaults file.

[iandol]

There is a valid workflow argument to have a default set of options yet a way to override it using the document itself, without other dependencies / files. Having a priority key or something would allow us to assign what should take precedence, so lets say:

---
title: Test
author: Jane Doe
priority: document
metadata:
  mainfont: Libertinus Serif
---

Test.

..could allow the document to override the defaults or command-line settings?. This is especially useful for those of us that use automation; we mostly want our defaults defined in our scripts that run pandoc in the background, but occasionally need to change something for a specific document[1]. The easiest way would be to use the document itself for this...

---

[1] this is one reason why I stick to pandocomatic rather than use defaults files, as you can use a default template but still override settings using the document itself: https://heerdebeer.org/Software/markdown/pandocomatic/#customizing-an-external-template-in-an-internal-template -- very flexible!