fix: .well-known static folder not working (#3676)

This folder is typically used for site metadata like `security.txt` and
other stuff.

Author: marvinhagemeister

packages/fresh/src/dev/builder_test.ts

@@ -281,6 +281,42 @@ Deno.test({
   sanitizeResources: false,
 });
 
+Deno.test({
+  name: "Builder - .well-known static files",
+  fn: async () => {
+    await using _tmp = await withTmpDir();
+    const tmp = _tmp.dir;
+
+    const foo = path.join(tmp, ".well-known", "foo.json");
+    await Deno.mkdir(path.dirname(foo), { recursive: true });
+    await Deno.writeTextFile(foo, JSON.stringify({ ok: true }));
+
+    const builder = new Builder({
+      outDir: path.join(tmp, "dist"),
+      staticDir: tmp,
+    });
+    const app = new App().use(staticFiles());
+    const abort = new AbortController();
+    const port = 8011;
+    await builder.listen(() => Promise.resolve(app), {
+      port,
+      signal: abort.signal,
+    });
+
+    const res = await fetch(
+      `http://localhost:${port}/.well-known/foo.json`,
+    );
+    const json = await res.json();
+    await abort.abort();
+
+    expect(res.ok).toBe(true);
+    expect(res.status).toBe(200);
+    expect(json).toEqual({ ok: true });
+  },
+  sanitizeOps: false,
+  sanitizeResources: false,
+});
+
 Deno.test({
   name: "Builder - write prod routePattern",
   fn: async () => {

packages/fresh/src/dev/dev_build_cache.ts

@@ -142,7 +142,7 @@ export class MemoryBuildCache<State> implements DevBuildCache<State> {
       for (let i = 0; i < transformed.length; i++) {
         const file = transformed[i];
         const relative = path.relative(this.#config.staticDir, file.path);
-        if (relative.startsWith(".")) {
+        if (relative.startsWith("..")) {
           throw new Error(
             `Processed file resolved outside of static dir ${file.path}`,
           );
@@ -158,7 +158,7 @@ export class MemoryBuildCache<State> implements DevBuildCache<State> {
       try {
         const filePath = path.join(this.#config.staticDir, pathname);
         const relative = path.relative(this.#config.staticDir, filePath);
-        if (!relative.startsWith(".") && (await Deno.stat(filePath)).isFile) {
+        if (!relative.startsWith("..") && (await Deno.stat(filePath)).isFile) {
           const pathname = new URL(relative, "http://localhost").pathname;
           this.addUnprocessedFile(pathname, this.#config.staticDir);
           return this.readFile(pathname);
@@ -301,8 +301,9 @@ export class DiskBuildCache<State> implements DevBuildCache<State> {
         includeDirs: false,
         includeFiles: true,
         followSymlinks: false,
-        // Skip any folder or file starting with a "."
-        skip: [/\/\.[^/]+(\/|$)/],
+        // Skip any folder or file starting with a ".", but allow
+        // ".well-known" for things like PWA manifests
+        skip: [/\/\.(?!well-known)[^/]+(\/|$)/],
       });
 
       for await (const entry of entries) {