Impossibility to fence a code chunk with the chunk option include: false?

[elenlefoll]

I have:

• searched the issue tracker for similar issues
• installed the latest version of Quarto CLI
• formatted my issue following the Bug Reports guide

Bug description

For a textbook I would like to explain to students that they can use the code chunk option include: false to run a chunk, but not display it or its output in their rendered document. I would like to be able to display this demo chunk in the rendered version of my textbook and, for this, I used the echo: fenced option. However, the problem is that the chunk is not displaying in the rendered doc (see reprex below).

Steps to reproduce

---
title: "Fencing a code chunk with option include: false"
date: last-modified
author: Elen Le Foll
---

For a textbook I would like to explain to students that they can use the code chunk option `include: false` to run a chunk, but not display it or its output in the rendered document. I would like to be able to display this demo chunk and for this I used the `echo: fenced` option. However, the problem is that the chunk is not displayed in the rendered doc.

```{r}

#| echo: fenced
#| label: demo-chunk
#| include: false

demoplot <- plot(1:10)

```

Actual behavior

The code chunk is not displayed in the rendered doc.

reprex.html

Expected behavior

The code chunk should be rendered including with the opening and closing backticks.

Your environment

• IDE: RStudio Version 2026.01.1+403 (2026.01.1+403)
• MacOS Sequoia 15.4.1 (24E263)

Quarto check output

Quarto 1.9.30
[✓] Checking environment information...
      Quarto cache location: /Users/lefoll/Library/Caches/quarto
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.8.3: OK
      Dart Sass version 1.87.0: OK
      Deno version 2.4.5: OK
      Typst version 0.14.2: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.9.30
      Path: /Applications/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: v2025.11
      Chromium: (not installed)
      Chrome Headless Shell: (not installed)
      VeraPDF: (not installed)

[✓] Checking LaTeX....................OK
      Using: TinyTex
      Path: /Users/lefoll/Library/TinyTeX/bin/universal-darwin
      Version: 2025

[✓] Checking Chrome Headless....................OK
      Using: Chrome found on system
      Path: /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
      Source: MacOS known location

[✓] Checking basic markdown render....OK

[✓] Checking R installation...........OK
      Version: 4.5.2
      Path: /Library/Frameworks/R.framework/Resources
      LibPaths:
        - /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/library
      knitr: 1.51
      rmarkdown: 2.30

[✓] Checking Knitr engine render......OK

[✓] Checking Python 3 installation....OK
      Version: 3.12.8 (Conda)
      Path: /Users/lefoll/miniconda3/bin/python
      Jupyter: (None)

      Jupyter is not available in this Python installation.
      Install with conda install jupyter

[✓] Checking Julia installation...

[mcanouil]

That's not a bug.
The result is exactly as expected:

Catch all for preventing any output (code or results) from being included in output.

Use escaping for these cases:

```{{r}}
#| label: demo-chunk
#| include: false

demoplot <- plot(1:10)
```

[elenlefoll]

Thanks for your quick answer. This is indeed a solution for displaying the code chunk as is, but it doesn't execute it, which is a problem for me as these code chunks are used to create objects that are called in future chunks in the textbook. So currently, I have to duplicate these chunks and make one escaped for displaying and keep the other for execution.

[cderv]

The problem here is the combo of include: false and echo: fenced

By saying include: false you are saying that this chunk should not be included in output. So no matter echo: fenced or echo: true, it won't show as include: false

So to specifically demo include: false you will need to duplicate, because echo: fenced won't help.

For other options, this will show code with options.

To avoid duplication, you may be able to come up with some R function to dynamically write the correct markdown based on a single source for the code cell content. Worth a try

[cderv]

Something like this

---
title: "Fencing a code chunk with option include: false"
date: last-modified
---

```{r}
#| label: demo-chunk
#| include: false

plot(1:10)
```

```{r}
#| label: escape_fun
#| include: false
escape_chunk <- function(label) {
    cell_code <- knitr::knit_code$get(label)
    cell_options <- attr(cell_code, "chunk_opts")
    yaml_options <- paste0("#| ", xfun::split_lines(yaml12::format_yaml(cell_options)))
    res <-  xfun::fenced_block(c(yaml_options, cell_code), attrs = "{{r}}")
    cat(res, sep = "\n")
}
```

```{r}
#| output: asis
#| echo: false
escape_chunk("demo-chunk")
```

And we can still show the plot
```{r}
#| label: demo-chunk
#| include: true
#| echo: false
```

This is using some tricks mentioned in the cookbook for knitr and rmarkdown https://yihui.org/rmarkdown-cookbook

And some internal logic to recreate the escaped cells for Quarto to do the right thing, without copy pasing your cell content.

Anyhow, hope this help find a custom solution for your need.

[elenlefoll]

Thanks a lot for your detailed reply and this workaround! I think that, for the present textbook project, I will stick to simply duplicating the chunks because I know that some of my students look at the textbook's .qmd source files and then get confused if they see things that they don't understand, but it's great to have these workarounds documented for future usage.