Bug description

Quarto seems to determine the computational engine only if:

• The engine parameter is set in yaml or
• The qmd file contains a code chunk

My expectation is that Quarto infer the computational engine if there is only inline code present in the document.

Unfortunately, that's not the case.

Not sure if this is a feature or a bug from the developers' perspective. For me, it's either a bug or a feature request.

Steps to reproduce

---
format: revealjs
execute: 
  eval: true
  echo: false
---

## Show the the icon

### `r fontawesome::fa(name = "route")`

Actual behavior

In the absence of either the engine param in yaml or a code chunk in the document's body, Quarto treats inline code as the <pre> tag.

If the engine param is specified, I get the icon I expect.

If a code block is present in the document--even if it's devoid of content--I also get the icon I expect.

Expected behavior

I expect--hope--that Quarto will see inline R code blocks and infer that I want the knitr engine.

For the reproducible example above, I expect to see the FontAwesome route icon.

Your environment

• IDE: VSCode. See details below.

Version: 1.99.3 (user setup)
Commit: 17baf841131aa23349f217ca7c570c76ee87b957
Date: 2025-04-15T23:18:46.076Z
Electron: 34.3.2
ElectronBuildId: 11161073
Chromium: 132.0.6834.210
Node.js: 20.18.3
V8: 13.2.152.41-electron.0
OS: Windows_NT x64 10.0.26100

• OS: Windows 11

Quarto check output

$ quarto check
Quarto 1.6.39
[>] Checking environment information...
      Quarto cache location: C:\Users\WB393438\AppData\Local\quarto
[>] Checking versions of quarto binary dependencies...
      Pandoc version 3.4.0: OK
      Dart Sass version 1.70.0: OK
      Deno version 1.46.3: OK
      Typst version 0.11.0: OK
[>] Checking versions of quarto dependencies......OK
[>] Checking Quarto installation......OK
      Version: 1.6.39
      Path: C:\WBG\Quarto\bin
      CodePage: 1252

[>] Checking tools....................OK
      Chromium: 869685
      TinyTeX: (not installed)

[>] Checking LaTeX....................OK
      Tex:  (not detected)

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

[>] Checking Python 3 installation....(None)

      Unable to locate an installed version of Python 3.
      Install Python 3 from https://www.python.org/downloads/

[>] Checking R installation...........OK
      Version: 4.4.1
      Path: C:/PROGRA~1/R/R-44~1.1
      LibPaths:
        - C:/Users/WB393438/r_libraries
        - C:/Program Files/R/R-4.4.1/library
      knitr: 1.49
      rmarkdown: 2.29

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