Fix babel error issue

when lang: en is passed, babel-english needs to be installed.

This follows up fix on tinytex R package too about new error handling

cause is new pandoc way to setup babel, and maybe new babel error in log

Author: cderv

src/command/render/latexmk/parse-error.ts

@@ -283,6 +283,12 @@ const packageMatchers = [
   { regex: /.*! LaTeX Error: File [`']([^']+)' not found.*/g },
   { regex: /.* [fF]ile ['`]?([^' ]+)'? not found.*/g },
   { regex: /.*the language definition file ([^\s]*).*/g },
+  {
+    regex: /.*! Package babel Error: Unknown option [`']([^'`]+)'[.].*/g,
+    filter: (match: string, _text: string) => {
+      return `${match}.ldf`;
+    },
+  },
   { regex: /.* \\(file ([^)]+)\\): cannot open .*/g },
   { regex: /.*file [`']([^']+)' .*is missing.*/g },
   { regex: /.*! CTeX fontset [`']([^']+)' is unavailable.*/g },

tests/docs/smoke-all/2025/11/04/13633.qmd

@@ -0,0 +1,20 @@
+---
+title: "Babel English Auto-Install (#13633)"
+format: pdf
+lang: en
+_quarto:
+  tests:
+    pdf: null
+---
+
+```{r}
+#| include: false
+
+# Remove babel-english package to test auto-installation
+if (tinytex::check_installed("babel-english")) {
+  message("Removing 'babel-english' package for the render")
+  tinytex::tlmgr_remove("babel-english")
+}
+```
+
+This document tests that Quarto correctly detects and auto-installs babel-english when rendering with `lang: en`.

tests/unit/latexmk/parse-error.test.ts

@@ -42,6 +42,7 @@ unitTest("Detect missing files with `findMissingFontsAndPackages`", async () =>
     (babel)                There is a locale ini file for this language.
     (babel)                If it’s the main language, try adding \`provide=*'
     (babel)                to the babel package options.`, "ngerman.ldf")
+  assertFound("! Package babel Error: Unknown option 'english'.", "english.ldf");
   assertFound("!pdfTeX error: pdflatex (file 8r.enc): cannot open encoding file for reading", "8r.enc");
   assertFound("! CTeX fontset `fandol' is unavailable in current mode", "fandol");
   assertFound("! CTeX fontset 'fandol' is unavailable in current mode", "fandol");