fix(typst): drop CSS generic font families from font-family lists

dev-docs/feature-format-matrix/qmd-files/css-properties/font-family/document.qmd

@@ -19,8 +19,11 @@ _quarto:
     typst:
       ensureTypstFileRegexMatches:
         -
-          - '#{set text\(font: \("Georgia", "serif"\)\); table\('
-        - []
+          # Georgia is kept; the CSS generic "serif" is dropped (not a real
+          # Typst font), leaving a single-element font tuple.
+          - '#{set text\(font: \("Georgia",\)\); table\('
+        -
+          - '"serif"'
 ---
 
 ```{=html}

news/changelog-1.10.md

@@ -30,7 +30,7 @@ All changes included in 1.10:
 
 ### `typst`
 
-- ([#12556](https://github.com/quarto-dev/quarto-cli/issues/12556)): Filter unavailable fonts from CSS `font-family` fallback lists before passing them to Typst, suppressing `unknown font family` warnings from Typst 1.12+ for fonts not installed locally. Available fonts are enumerated via `typst fonts` and cached per project.
+- ([#12556](https://github.com/quarto-dev/quarto-cli/issues/12556)): Filter unavailable fonts from CSS `font-family` fallback lists before passing them to Typst, suppressing `unknown font family` warnings from Typst 1.12+ for fonts not installed locally. Available fonts are enumerated via `typst fonts` and cached per project. CSS generic family keywords (`serif`, `sans-serif`, `monospace`, `cursive`, `fantasy`, `math`) are also dropped, as Typst has no concept of them and would otherwise warn — for example a table styled with `font-family: Arial, sans-serif` no longer emits a warning for `sans-serif`.
 - ([#14261](https://github.com/quarto-dev/quarto-cli/issues/14261)): Fix theorem/example block titles containing inline code producing invalid Typst markup when syntax highlighting is applied.
 - ([#14460](https://github.com/quarto-dev/quarto-cli/issues/14460)): Fix CSS `border` and `border-color` declarations losing tokens that precede an `rgb()`/`rgba()` color (e.g. `border: 0px solid rgb(255, 0, 0)` rendering as a 2.25pt border instead of being suppressed). Also fixes: `var(--brand-NAME)` references crashing the Typst CSS translator when `NAME` contained digits (e.g. `--brand-red-50`); a crash when an `rgba()` alpha is unparseable; the `dvmin` length unit being silently rejected (a stray space in the unit table); CSS keywords like `BOLD` not matching as `bold` (CSS keywords are case-insensitive); invalid hex colors like `#fffff` being silently accepted as 2-component colors.
 - ([#14511](https://github.com/quarto-dev/quarto-cli/issues/14511)): Fix brand fonts downloaded for a Typst book project not being passed to `typst compile`, causing `unknown font family` warnings and fallback to Libertinus Serif.

src/resources/filters/modules/typst_css.lua

@@ -658,10 +658,6 @@ end
 
 local _available_fonts = nil
 local _fonts_initialized = false
-local _generic_families = {
-  ["serif"] = true, ["sans-serif"] = true, ["monospace"] = true,
-  ["cursive"] = true, ["fantasy"] = true, ["math"] = true,
-}
 
 local function init_available_fonts(list)
   _fonts_initialized = true
@@ -694,7 +690,11 @@ local function translate_font_family_list(sl)
       local cleaned = dequote(s)
       local quoted = quote(cleaned)
       table.insert(all_strings, quoted)
-      if not _available_fonts or _available_fonts[cleaned:lower()] or _generic_families[cleaned:lower()] then
+      -- CSS generic families (serif, sans-serif, monospace, ...) are not real
+      -- Typst fonts and trigger "unknown font family" warnings, so they are
+      -- not kept here. When no real font remains, the all-filtered fallback
+      -- below re-emits the original list to avoid an empty (illegal) tuple.
+      if not _available_fonts or _available_fonts[cleaned:lower()] then
         table.insert(filtered, quoted)
       end
     end

tests/docs/smoke-all/typst/brand-yaml/font-filtering-generics/font-filtering-generics.qmd

@@ -8,13 +8,17 @@ _quarto:
     typst:
       ensureTypstFileRegexMatches:
         -
-          # CSS generic families (sans-serif, monospace) preserved alongside real fonts
-          - 'font: \("Roboto", "sans-serif"\),'
-          - 'codefont: \("Inconsolata", "monospace"\),'
-        - []
+          # Real available fonts are kept; CSS generic families are dropped.
+          - 'font: \("Roboto",\),'
+          - 'codefont: \("Inconsolata",\),'
+        -
+          # Generic families must not reach Typst: they are not real fonts and
+          # would trigger "unknown font family" warnings.
+          - '"sans-serif"'
+          - '"monospace"'
 ---
 
-Verifies that CSS generic font family names (sans-serif, monospace, serif,
-cursive, fantasy, math) are preserved during font availability filtering,
-since they are valid fallback specifiers even though they don't appear in
-`typst fonts` output.
+Verifies that CSS generic font family names are stripped from the Typst
+font-family output during availability filtering. They are not real Typst
+fonts and would otherwise trigger "unknown font family" warnings. The real
+brand fonts (Roboto, Inconsolata, both downloaded from Google) are preserved.

tests/unit-lua/typst-css.test.lua

@@ -537,4 +537,31 @@ function TestFontFiltering:testEmptyMetaListNoFiltering()
     '("Inter", "Arial")')
 end
 
+function TestFontFiltering:testStripsGenericWhenRealFontAvailable()
+  -- CSS generic families (sans-serif, serif, ...) are not real Typst fonts;
+  -- Typst warns "unknown font family" on them. When an available real font
+  -- remains, the generic is pure dead weight and is dropped.
+  typst_css.init_available_fonts({ 'arial' })
+  lu.assertEquals(
+    typst_css.translate_font_family_list('Arial, sans-serif'),
+    '("Arial",)')
+end
+
+function TestFontFiltering:testStripsGenericKeepsMultipleReal()
+  typst_css.init_available_fonts({ 'roboto', 'inconsolata' })
+  lu.assertEquals(
+    typst_css.translate_font_family_list('Roboto, Inconsolata, monospace'),
+    '("Roboto", "Inconsolata")')
+end
+
+function TestFontFiltering:testGenericOnlyFallsBackToOriginal()
+  -- A generic-only stack filters to empty; the all-filtered fallback
+  -- re-emits the original so Typst never receives an empty tuple (a hard
+  -- error). Typst still warns here, but the document compiles.
+  typst_css.init_available_fonts({ 'arial' })
+  lu.assertEquals(
+    typst_css.translate_font_family_list('sans-serif'),
+    '("sans-serif",)')
+end
+
 os.exit(lu.LuaUnit.run())