Unnecessary local copies of Typst extensions [prerelease]

[CoryMcCartan]

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

Basic Typst documents that don't need any extensions still download the basic extensions to .quarto/, which creates 1.5MB of unecessary files.

Steps to reproduce

Create an empty directory and save the following as test.qmd

---
title: A test
format: 
    typst:
        keep-typ: true
---

Run quarto render test.qmd

Actual behavior

Opening test.typ confirms no use of any extensions.
But a .quarto/ directory is created with 6 bundled extensions weighing 1.5 MB (vs 65B for the qmd, 10kB for the typ, and 8 kB for the PDF)

Expected behavior

.quarto/typst/packages/ should only be created or non-empty if the extensions are needed to render the document. 1.5 MB overhead on every single document seems quite excessive.

Your environment

• OS: MacOS 15.7.4

Quarto check output

Quarto 1.9.23
[✓] Checking environment information...
      Quarto cache location: /Users/cmccartan/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: 1.9.23
      Path: /Applications/quarto/bin

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

[✓] Checking LaTeX....................OK
      Using: TinyTex
      Path: /Users/cmccartan/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: 4.5.0
      Path: /Library/Frameworks/R.framework/Resources
      LibPaths:
        - /Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/library
      knitr: 1.50
      rmarkdown: 2.29

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

[✓] Checking Python 3 installation....OK
      Version: 3.9.6
      Path: /Library/Developer/CommandLineTools/usr/bin/python3
      Jupyter: (None)

      Jupyter is not available in this Python installation.
      Install with python3 -m pip install jupyter

[✓] Checking Julia installation...

[gordonwoodhull]

Thanks @CoryMcCartan!

Root cause: currently typst-gather parses Pandoc templates for includes, across Quarto and active extensions, and then we stage all of them before compiling. (Typst has a very resilient parser and has no problem parsing the imports in Pandoc templates even though these files are not syntactically valid Typst.)

Instead of staging everything, we should also parse the final generated typst document, after the templates are resolved, and use that to determine what to stage. It's the same parsing at render time.

It's too big a change to put into the 1.9 release, but we'll implement in 1.10 and can consider backporting.

Related

• move typst-gather out of core build #13983 would make typst-gather easier to develop independently