feat: normalize content layer IDs

packages/starlight/__tests__/basics/routing.test.ts

@@ -22,15 +22,15 @@ test('test suite is using correct env', () => {
 
 test('route slugs are normalized', () => {
 	const indexRoute = routes.find(
-		(route) => route.id === (project.legacyCollections ? 'index.mdx' : 'index')
+		(route) => route.id === (project.legacyCollections ? 'index.mdx' : '')
 	);
 	expect(indexRoute?.slug).toBe('');
 });
 
 test('routes contain copy of original doc as entry', async () => {
 	const docs = await getCollection('docs');
 	for (const route of routes) {
-		const doc = docs.find((doc) => doc.id === route.id);
+		const doc = docs.find((doc) => doc.id === route.id || (doc.id === 'index' && route.id === ''));
 		if (!doc) throw new Error('Expected to find doc for route ' + route.id);
 		// Compare without slug as slugs can be normalized.
 		const { slug: _, ...entry } = route.entry;
@@ -43,7 +43,10 @@ test('routes contain copy of original doc as entry', async () => {
 			const { slug: __, ...legacyInput } = doc;
 			expect(legacyEntry).toEqual(legacyInput);
 		} else {
-			expect(entry).toEqual(doc);
+			// Compare without ids as ids can be normalized when using loaders.
+			const { id: _, ...loaderEntry } = entry;
+			const { id: __, ...loaderInput } = doc;
+			expect(loaderEntry).toEqual(loaderInput);
 		}
 	}
 });

packages/starlight/__tests__/i18n-single-root-locale/routing.test.ts

@@ -14,7 +14,7 @@ vi.mock('astro:content', async () =>
 
 test('route slugs are normalized', () => {
 	const indexRoute = routes.find(
-		(route) => route.id === (project.legacyCollections ? 'index.mdx' : 'index')
+		(route) => route.id === (project.legacyCollections ? 'index.mdx' : '')
 	);
 	expect(indexRoute?.slug).toBe('');
 });

packages/starlight/utils/navigation.ts

@@ -205,8 +205,8 @@ function pathsMatch(pathA: string, pathB: string) {
 function getBreadcrumbs(path: string, baseDir: string): string[] {
 	// Strip extension from path.
 	const pathWithoutExt = stripExtension(path);
-	// Index paths will match `baseDir` and don’t include breadcrumbs.
-	if (pathWithoutExt === baseDir) return [];
+	// Index paths will match `baseDir` but we still need to consider them as a single segment.
+	if (pathWithoutExt === baseDir) return [path];
 	// Ensure base directory ends in a trailing slash.
 	baseDir = ensureTrailingSlash(baseDir);
 	// Strip base directory from path if present.
@@ -228,9 +228,6 @@ function treeify(routes: Route[], baseDir: string): Dir {
 		// Build the tree
 		.forEach((doc) => {
 			const parts = getBreadcrumbs(doc.id, baseDir);
-			// If the breadcrumb is empty, the document is at the root level so we can fallback to the
-			// document ID.
-			if (parts.length === 0) parts.push(doc.id);
 			let currentNode = treeRoot;
 
 			parts.forEach((part, index) => {

packages/starlight/utils/routing.ts

@@ -64,8 +64,11 @@ const normalizeIndexSlug = (slug: string) => (slug === 'index' ? '' : slug);
 
 /** Normalize the different collection entry we can get from a legacy collection or a loader. */
 export function normalizeCollectionEntry(entry: StarlightDocsCollectionEntry): StarlightDocsEntry {
+	const slug = normalizeIndexSlug(entry.slug ?? entry.id);
 	return {
 		...entry,
+		// In a collection with a loader, the `id` is a slug and should be normalized.
+		id: entry.slug ? entry.id : slug,
 		// In a legacy collection, the `filePath` property doesn't exist.
 		filePath: entry.filePath ?? `${getCollectionPathFromRoot('docs', project)}/${entry.id}`,
 		// In a collection with a loader, the `slug` property is replaced by the `id`.