monofontfallback fonts not auto-installed — luaotfload error format not recognized

[cderv]

When monofontfallback lists a font not installed on the system, lualatex fails and Quarto does not attempt to auto-install the missing font. The error format luaotfload emits for fallback-chain fonts is not recognized by Quarto's missing-package detector.

Error

The log contains:

luaotfload | db : Reload initiated (formats: otf,ttf,ttc); reason: Font "DejaVu Sans Mono;-fallback" not found.
luaotfload | resolve : sequence of 3 lookups yielded nothing appropriate.

Quarto's packageMatchers covers ! Font ... not loadable, ! .*The font "X" cannot be found, (fontspec) The font "X" cannot be, and similar patterns — but none match luaotfload | ... reason: Font "X" not found.

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

Lines 272 to 293 in 4127c26

	const packageMatchers = [
	// Fonts
	{
	regex: /.*! Font [^=]+=([^ ]+).+ not loadable.*/g,
	filter: formatFontFilter,
	},
	{
	regex: /.*! .*The font "([^"]+)" cannot be found.*/g,
	filter: formatFontFilter,
	},
	{
	regex: /.*!.+ error:.+\(file ([^)]+)\): .*/g,
	filter: formatFontFilter,
	},
	{
	regex: /.*Unable to find TFM file "([^"]+)".*/g,
	filter: formatFontFilter,
	},
	{
	regex: /.*\(fontspec\)\s+The font "([^"]+)" cannot be.*/g,
	filter: formatFontFilter,
	},

Why the primary font case works but monofontfallback does not

When the primary monofont is missing, luaotfload fails first but fontspec then also emits ! Package fontspec Error: The font "X" cannot be found, which is matched. The monofontfallback path registers fonts via luaotfload.add_fallback() — when that fails, fontspec does not fire its own error, so only the unrecognized luaotfload message appears.

Secondary issue: ;-fallback suffix corrupts the search term

luaotfload appends ;-fallback internally to each fallback-chain entry to prevent recursive fallback resolution. Even if a pattern matched, the extracted name DejaVu Sans Mono;-fallback would produce a broken fontSearchTerm regex:

DejaVu\s*Sans\s*Mono;-fallback(-(Bold|Italic|Regular).*)?[.](tfm|afm|mf|otf|ttf)

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

Lines 361 to 364 in 4127c26

	function fontSearchTerm(font: string): string {
	const fontPattern = font.replace(/\s+/g, "\\s*");
	return `${fontPattern}(-(Bold|Italic|Regular).*)?[.](tfm|afm|mf|otf|ttf)`;
	}

After stripping ;-fallback, fontSearchTerm("DejaVu Sans Mono") produces DejaVu\s*Sans\s*Mono(-(Bold|Italic|Regular).*)?[.](tfm|afm|mf|otf|ttf) — the \s* matches zero whitespace, so DejaVuSansMono.otf would match and tlmgr search would find the dejavu CTAN package.

Fix direction

Two changes to parse-error.ts:

1. A new pattern for the luaotfload format: /.*luaotfload.*reason: Font "([^"]+)" not found.*/g
2. A filter that strips the ;-fallback suffix before passing to formatFontFilter

A unit test case can go in the existing tests/unit/latexmk/parse-error.test.ts.

Related

• Error rendering PDF with ∈ symbol in Julia cells #14553 — user report that surfaced this
• Font package auto-install fails for fonts with spaces in names #13732 — prior fix for spaces in font names in fontSearchTerm