Add error message when `{{< include >}}` is used in invalid position

[brenobeirigo]

Bug description

I would like to use "include" to generate a list with info I will use across the document.
The rendering, however, is an empty bullet.

Example:

Assume the file warehousing_course_ilo_explain.qmd has the content ILO1.

Then, the following:

Upon finishing the MSc Warehousing course, students will be able to:

- {{< include warehousing_course_ilo_explain.qmd >}}

{{< include warehousing_course_ilo_explain.qmd >}}

Results:

Upon finishing the MSc Warehousing course, students will be able to:

ILO1

The bug happens both in Windows and Linux (WSL) + VS Code.

Checklist

• Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
• Please format your issue so it is easier for us to read the bug report.
• Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
• Please document the operating system you're running. If on Linux, please provide the specific distribution.

[cderv]

I believe include is used to insert part of a valid qmd document in another main one. Include works by replacing the content inside the document if I am right.

This means that if you include content needs to be a list, the list syntax should be used inside your child document.

Now I understand that you may want a different behavior if your included document is supposed to be used elsewhere without a list. Is that what happens here ?

@cscheid maybe you can confirm ?

[cscheid]

The include shortcode needs to exist by itself in a new line. That's by design, precisely to avoid complications that arise in situations like this. Consider the inclusion inside a list: should we indent the contents to match? The semantics are confusing on either answer.

We should improve the situation and emit an error message if includes don't start at the beginning of a line, and I've also just updated our docs to reflect this limitation. (I thought our documentation already indicated that, but it doesn't. My apologies.)

If you need to do this kind of fine-grained structure-aware content inclusion, we recommend the usage of Lua filters.

(If you need structure-aware content inclusion before engine execution, unfortunately that's currently not possible in quarto.)

[mcanouil]

Seems to be a duplicate of:

• typescript shortcodes need to be in a line by themselves #1767