**OS:** Pop!_OS 22.04 LTS x86_64
**Quarto version:** 0.9.550

Minimal example to reproduce error:

```sh
quarto create-project mybook --type book
```
Add conditional content to bottom of intro.qmd:

```
# Introduction

This is a book created from markdown and executable code.

See @knuth84 for additional discussion of literate programming.

::: {.content-visible when-format="html"}

Will only appear in HTML.

:::
```
Render book:

```sh
quarto render --to all
```
Encountered error:

```sh
Error running filter /opt/quarto/share/filters/quarto-pre/quarto-pre.lua:
/opt/quarto/share/filters/quarto-pre/quarto-pre.lua:217: attempt to call a nil value (field 'formatMatches')
stack traceback:
	/opt/quarto/share/filters/quarto-pre/quarto-pre.lua:233: in function 'handleVisible'
	(...tail calls...)
```

Output of `quarto check`

```
[✓] Checking Quarto installation......OK
      Version: 0.9.550
      Path: /opt/quarto/bin

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

[✓] Checking Python 3 installation....OK
      Version: 3.9.7 (Conda)
      Path: /home/bjorn/miniconda3/bin/python
      Jupyter: 4.9.2
      Kernels: python3

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

[✓] Checking R installation...........OK
      Version: 4.2.0
      Path: /usr/lib/R
      LibPaths:
        - /home/bjorn/R/x86_64-pc-linux-gnu-library/4.2
        - /usr/local/lib/R/site-library
        - /usr/lib/R/site-library
        - /usr/lib/R/library
      rmarkdown: 2.14

[✓] Checking Knitr engine render......OK
```
The last version (that I know of) that did **not** produce an error was 0.9.426


dragonstyle
2022-06-08T20:09:18Z
bbartholdy
Future
open
Conditional content error
https://github.com/quarto-dev/quarto-cli/issues/1108