Fonts: fix typing for disabled fallbacks (empty array)

.changeset/chatty-taxes-retire.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes a bug where empty fallbacks could not be provided when using the experimental fonts API

packages/astro/src/assets/fonts/config.ts

@@ -60,7 +60,7 @@ const fallbacksSchema = z.object({
 
 	 * If the last font in the `fallbacks` array is a [generic family name](https://developer.mozilla.org/en-US/docs/Web/CSS/font-family#generic-name), an [optimized fallback](https://developer.chrome.com/blog/font-fallbacks) using font metrics will be generated. To disable this optimization, set `optimizedFallbacks` to false.
 	 */
-	fallbacks: z.array(z.string()).nonempty().optional(),
+	fallbacks: z.array(z.string()).optional(),
 	/**
 	 * @default `true`
 	 *

packages/astro/test/types/define-config.ts

@@ -1,7 +1,7 @@
 import { describe, it } from 'node:test';
 import { expectTypeOf } from 'expect-type';
 import type { AstroFontProvider, FontFamily } from '../../dist/assets/fonts/types.js';
-import { defineAstroFontProvider } from '../../dist/config/entrypoint.js';
+import { defineAstroFontProvider, fontProviders } from '../../dist/config/entrypoint.js';
 import { defineConfig } from '../../dist/config/index.js';
 import type { AstroUserConfig } from '../../dist/types/public/index.js';
 
@@ -138,4 +138,40 @@ describe('defineConfig()', () => {
 			},
 		);
 	});
+
+	it('Allows disabling font fallbacks', () => {
+		assertType(
+			defineConfig({
+				experimental: {
+					fonts: [
+						{
+							provider: fontProviders.google(),
+							name: 'Roboto',
+							fallbacks: [],
+							cssVariable: '--font-roboto',
+						},
+					],
+				},
+			}),
+			(config) => {
+				expectTypeOf(config).toEqualTypeOf<
+					AstroUserConfig<
+						never,
+						never,
+						[
+							{
+								readonly provider: {
+									entrypoint: string | URL;
+									config?: Record<string, any> | undefined;
+								};
+								readonly name: 'Roboto';
+								readonly fallbacks: [];
+								readonly cssVariable: '--font-roboto';
+							},
+						]
+					>
+				>();
+			},
+		);
+	});
 });

packages/astro/test/units/config/config-validate.test.js

@@ -4,6 +4,7 @@ import { describe, it } from 'node:test';
 import { stripVTControlCharacters } from 'node:util';
 import { z } from 'zod';
 import { validateConfig as _validateConfig } from '../../../dist/core/config/validate.js';
+import { fontProviders } from '../../../dist/assets/fonts/providers/index.js';
 import { formatConfigErrorMessage } from '../../../dist/core/messages.js';
 import { envField } from '../../../dist/env/config.js';
 
@@ -460,5 +461,22 @@ describe('Config Validation', () => {
 				}),
 			);
 		});
+
+		it('Should allow empty font fallbacks', () => {
+			assert.doesNotThrow(() =>
+				validateConfig({
+					experimental: {
+						fonts: [
+							{
+								provider: fontProviders.google(),
+								name: 'Roboto',
+								fallbacks: [],
+								cssVariable: '--font-roboto',
+							},
+						],
+					},
+				}),
+			);
+		});
 	});
 });