fix: correctly resolve hooks entry file when directory exists (#13144)

fixes #13100

This PR adds a check to see if an index file exists in the related directory before resolving to that path. Directories without an index file should correctly fallback to the non-directory path.

.changeset/brown-bats-mate.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: correctly resolve hooks file when a similarly named directory exists

packages/kit/src/utils/filesystem.js

@@ -169,8 +169,9 @@ export function from_fs(str) {
 export function resolve_entry(entry) {
 	if (fs.existsSync(entry)) {
 		const stats = fs.statSync(entry);
-		if (stats.isDirectory()) {
-			return resolve_entry(path.join(entry, 'index'));
+		const index = path.join(entry, 'index');
+		if (stats.isDirectory() && fs.existsSync(index)) {
+			return resolve_entry(index);
 		}
 
 		return entry;

packages/kit/src/utils/filesystem.spec.js

@@ -105,3 +105,10 @@ test('ignores hooks.server folder when resolving hooks', () => {
 
 	expect(resolve_entry(source_dir + '/hooks')).null;
 });
+
+test('ignores hooks folder that has no index file when resolving hooks', () => {
+	write('hooks/not-index.js', '');
+	write('hooks.js', '');
+
+	expect(resolve_entry(source_dir + '/hooks')).toBe(source_dir + '/hooks');
+});