From b691468f5501d5a706f1530e47809039c2669d8d Mon Sep 17 00:00:00 2001
From: Kristian Papadakis <98982554+kristian-presso@users.noreply.github.com>
Date: Fri, 16 Oct 2026 19:47:25 +0100
Subject: [PATCH] fix(basic-host): serve sandbox.html when the checkout is
 under a dotted directory

`res.sendFile` with an absolute path and no `root` makes `send` check every
segment of the path for dotfiles, and it ignores dotfiles by default. So
when any directory above examples/basic-host starts with a dot (`.cache/`,
`.runs/`, a `.worktrees/` checkout), the sandbox server answers 404 for
sandbox.html while the host page, served through `express.static` with a
root, loads fine. The View then never renders.

Pass the file name with `root: DIRECTORY` so only the relative path is
checked, as `express.static` already does for the host page.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DyfRBGJuWRersRLswfqPwd
---
 examples/basic-host/serve.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/examples/basic-host/serve.ts b/examples/basic-host/serve.ts
index bc3fbff14..941a8c846 100644
--- a/examples/basic-host/serve.ts
+++ b/examples/basic-host/serve.ts
@@ -124,7 +124,9 @@ sandboxApp.get(["/", "/sandbox.html"], (req, res) => {
   res.setHeader("Pragma", "no-cache");
   res.setHeader("Expires", "0");
 
-  res.sendFile(join(DIRECTORY, "sandbox.html"));
+  // With `root`, only the relative path is checked for dotfiles. An absolute path would 404
+  // whenever any directory above DIRECTORY starts with a dot (e.g. `.cache/`).
+  res.sendFile("sandbox.html", { root: DIRECTORY });
 });
 
 sandboxApp.use((_req, res) => {