Markdown Extensions for Code Blocks Not Working Properly with ‘templ’ Language

[indaco]

Describe the bug

I noticed that certain Markdown extensions for code blocks do not work as expected in VitePress when using the templ language, while they work properly for other languages like js. Specifically:

• Not Working Properly:
  • Focus in Code Blocks
  • Colored Diffs in Code Blocks
  • Errors and Warnings in Code Blocks
• Working as Expected:
  • Line Highlighting in Code Blocks

Thanks

Reproduction

https://stackblitz.com/edit/vite-4gtyqrtf?file=docs%2Findex.md

Visit the demo page by clicking the MD Extensions Issue with Templ button on the homepage.

Expected behavior

All supported Markdown extensions for code blocks should render correctly, regardless of the specified language, as long as the language is supported by shiki. Since templ is a supported language, these extensions should work as expected, similar to how Line Highlighting currently works.

System Info

System:
    OS: macOS 15.2
    CPU: (8) arm64 Apple M3
    Memory: 434.31 MB / 24.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.18.1 - ~/.nvm/versions/node/v20.18.1/bin/node
    npm: 10.8.2 - ~/.nvm/versions/node/v20.18.1/bin/npm
    pnpm: 9.15.4 - ~/Library/pnpm/pnpm
  Browsers:
    Chrome: 131.0.6778.267
    Safari: 18.2
  npmPackages:
    vitepress: ^1.6.3 => 1.6.3

Additional context

No response

Validations

• Check if you're on the latest VitePress version.
• Follow our Code of Conduct
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

[brc-dd]

Track it with shiki. It's a known issue.

Duplicate of #3503, #4087