dir-list already sent with trailing slash

[jessekrubin]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

5.x.x

Plugin version

8.x.x

Node.js version

20

Operating system

Linux

Operating system version (i.e. 20.04, 11.3, 10)

rhel8 and ms windows

Description

When using the default json list for directories and fastify static trailing slashes trigger a reply-already sent error internally.

repro: https://github.com/jessekrubin/fastify-static-reply-sent

// fastify

import path from "node:path";
import Fastify from "fastify";

import FastifyStatic from "@fastify/static";
const fastify = Fastify({ logger: { level: "trace" } });

const pwd = process.cwd();
const root = path.join(pwd, "/node_modules");
console.log(root);
fastify
  .register(FastifyStatic, {
    root,
    redirect: false, // redirect true makes problem always happen
    prefix: "/node_modules",
    index: false,
    list: true,
  })
  .listen({ port: 3000 }, (err) => {
    if (err) throw err;
  });

// dir routes give me a 'already sent' error msg!

// NO PROBLEMO:
//   http://localhost:3000/node_modules/@fastify   <-- no trailing slash
// HAS PROBLEM:
//   http://localhost:3000/node_modules/           <-- trailing slash
//   http://localhost:3000/node_modules/@fastify/  <-- trailing slash

Link to code that reproduces the bug

https://github.com/jessekrubin/fastify-static-reply-sent

Expected Behavior

not throw an error or document how I am supposed to configure this?

[jessekrubin]

adding the trailing slash causes problem-o-s

jesse@corbett[[fastify-static-bug]]$ node --watch thingy.js | pino-pretty &
[16:13:24.557] INFO (149519): Server listening at http://127.0.0.1:3000

jesse@corbett[[fastify-static-bug]]$ curl -s http://localhost:3000/node_modules/@fastify/ > outputshit.json && sleep 1 && echo -------prob-------- && cat outputshit.json | jq
[16:13:48.497] INFO (149519): incoming request
    reqId: "req-1"
    req: {
      "method": "GET",
      "url": "/node_modules/@fastify/",
      "host": "localhost:3000",
      "remoteAddress": "127.0.0.1",
      "remotePort": 49692
    }
[16:13:48.502] WARN (149519): Reply was already sent, did you forget to "return reply" in "/node_modules/@fastify/" (GET)?
    reqId: "req-1"
    err: {
      "type": "FastifyError",
      "message": "Reply was already sent, did you forget to \"return reply\" in \"/node_modules/@fastify/\" (GET)?",
      "stack":
          FastifyError: Reply was already sent, did you forget to "return reply" in "/node_modules/@fastify/" (GET)?
              at Reply.send (/home/jesse/fastify-static-bug/node_modules/.pnpm/[email protected]/node_modules/fastify/lib/reply.js:132:26)
              at pumpSendToReply (/home/jesse/fastify-static-bug/node_modules/.pnpm/@[email protected]/node_modules/@fastify/static/index.js:350:21)
      "code": "FST_ERR_REP_ALREADY_SENT",
      "name": "FastifyError",
      "statusCode": 500
    }
[16:13:48.503] INFO (149519): request completed
    reqId: "req-1"
    res: {
      "statusCode": 200
    }
    responseTime: 5.25226900074631
-------prob--------
{
  "dirs": [
    "static"
  ],
  "files": []
}
jesse@corbett[[fastify-static-bug]]$ curl -s http://localhost:3000/node_modules/@fastify > outputshit.json && sleep 1 && echo -------NO-prob-no-trailing-slash-------- && cat outputshit.json | jq
[16:14:07.158] INFO (149519): incoming request
    reqId: "req-2"
    req: {
      "method": "GET",
      "url": "/node_modules/@fastify",
      "host": "localhost:3000",
      "remoteAddress": "127.0.0.1",
      "remotePort": 56780
    }
[16:14:07.159] INFO (149519): request completed
    reqId: "req-2"
    res: {
      "statusCode": 200
    }
    responseTime: 0.9850010005757213
-------NO-prob-no-trailing-slash--------
{
  "dirs": [
    "static"
  ],
  "files": []
}