Python syntax error indicator caret character leads to LaTeX compilation error

[lrrichter]

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

Dear maintainers,

when I want to include Python error messages with error: true in the LaTeX-generated pdf strange LaTeX code is generated at this position and the LaTeX compilation fails. Setting Error: false stops at this point with the expected error message on the console. Suppressing the output with output: false helps and completes the compilation of the pdf without the error message in the resulting document.

Steps to reproduce

---
title: "Debug Color Parsing Problems 3"
subtitle: "DCPP"
author: "LR"
date: "07.11.25"
execute:
  echo: true
  error: true
format:
  beamer: 
    echo: true
    highlight-style: gruvbox-dark
    code-overflow: wrap
    code-line-numbers: true
---




## Code with Syntax Problem

```{python}

def my_func(a=10, b):
    print(a)
    print(b)

my_func(5)
```

Actual behavior

It stops typesetting with a LaTeX error complaining about an unknown command \textasciicaret.
Adding #| output: false allows to compile the file but without the output of the cell

It worked in the past, but an update (I do not which) seemed to break it.

Expected behavior

I expect the colored error message in the rendered pdf similar as it appears on my console.

Your environment

IDE: VisualCode
Version: 1.105.1 (Universal)
Commit: 7d842fb85a0275a4a8e4d7e040d2625abbf7f084
Datum: 2025-10-14T22:33:36.618Z
Electron: 37.6.0
ElectronBuildId: 12502201
Chromium: 138.0.7204.251
Node.js: 22.19.0
V8: 13.8.258.32-electron.0
Betriebssystem: Darwin arm64 24.6.0

OS: MacOS Sequoia 15.7.1 (24G231)

Quarto check output

Quarto 1.9.10
[✓] Checking environment information...
      Quarto cache location: /Users/richter/Library/Caches/quarto
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.6.3: OK
      Dart Sass version 1.87.0: OK
      NOTE: Deno version 2.4.5 does not strictly match 2.3.1 and strict checking is enabled. Please use 2.3.1.
      Typst version 0.13.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.9.10
      Path: /Applications/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: v2025.11
      Chromium: 869685

[✓] Checking LaTeX....................OK
      Using: TinyTex
      Path: /Users/richter/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

WARN: Specified QUARTO_PYTHON '/Users/richter/opt/anaconda3/envs/runquarto/bin/python' does not exist
WARN: No python binary found in specified QUARTO_PYTHON location '/Users/_____/opt/anaconda3/envs/runquarto/bin/python'
[✓] Checking Python 3 installation....OK
      Version: 3.12.12 (Conda)
      Path: /opt/anaconda3/bin/python
      Jupyter: 5.8.1
      Kernels: python3

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

[✓] Checking R installation...........(None)

      Unable to locate an installed version of R.
      Install R from https://cloud.r-project.org/

[mcanouil]

Note that it works for "real" errors:

--- 
format: pdf
execute:
  error: true
---

```{python}
def myfun(val):
    if val <= 0:
        raise ValueError()


myfun(-3)
```

The issue is about the ASCII code emitted in this particular case: ^ used to mark the location of the issue that is converted by Quarto to \textasciicaret{} which is not recognised.

• quarto-cli/src/resources/filters/quarto-post/latex.lua

  Line 605 in 76d2b98

  return line:gsub("[\\]", uuid):gsub("([{}$%&%_])", "\\%1"):gsub("[%^]", "\\textasciicaret{}"):gsub("[~]", "\\textasciitilde{}"):gsub(uuid, "\\textbackslash{}")

Changing the command to \textasciicircum{} solves the issue.

The other commands also work.

[lrrichter]

Note that it works for "real" errors:

You are right. I double checked my mini example and removed the suspected exceptions from the post text, leaving only syntax error messages from the interpreter over. I had to process ~ 200 slides about Python programming covering also different kinds of mistakes and the slides behaved nicely before and may have been dulled at the end.

I am not familiar with patching. Does it make sense to wait at least for the next prerelease or should I try a checkout?

Good job and thanks for your effort!

[mcanouil]

There is no fix implemented right now. The workaround left is for you to output to format: latex, then post-process it.

Or use a lua filter:

--- 
format: pdf
filters:
  - path: textasciicaret-fix.lua
    at: post-quarto
execute:
  error: true
---

```{python}

def my_func(a=10, b):
    print(a)
    print(b)

my_func(5)
```

function RawBlock(el)
  if quarto.doc.is_format("latex") then
    el.text = el.text:gsub("\\textasciicaret", "\\textasciicircum")
    return el
  end
end

[lrrichter]

Thank you for your answer. Please consider my question answered.

[mcanouil]

I'm reopening because I believe there is something to be done.
I only provided a workaround to unblock you.

[mcanouil]

Could you edit the title of the issue as it is misleading since the issue has nothing to day with colours.

[bflrmol-code]

The edit button does not show anywhere. Any idea? BTW: Proposed new title:"Python syntax error indicator '^' leads to LaTeX error". If you can change the title, please feel free to do it.

[mcanouil]

@bflrmol-code because only the author (and maintainers/owner roles) can edit.