6.0.0-beta.10 regression, https server lost http2 support (back to http1.1)

[sai-cb]

Describe the bug

Starting with the 6.0.0-beta.10 release (inclusive of the stable v6.0.0 release), using server.https in the Vite config no longer enables http2 as the doc indicates:

https://vite.dev/config/server-options#server-https

Enable TLS + HTTP/2.

Instead, all assets are served over http1.1. This can slow down loading assets from the dev server for complex project with lots of modules using https, but this is also critical as it breaks streaming support through custom dev server reverse proxy plugins (http1.1 does not support more than a few concurrent streaming connections)

Reproduction

https://stackblitz.com/edit/vitejs-vite-1lmesq?file=vite.config.ts

Steps to reproduce

Here's a vite.config.ts configuration with a self-signed certificate to reproduce this case:

import { defineConfig } from 'vite';

const HTTPS_CERTIFICATE = `-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

`;

export default defineConfig(() => {
  return {
    server: {
      port: 4000,
      https: {
        cert: HTTPS_CERTIFICATE,
        key: HTTPS_CERTIFICATE,
      },
    },
  };
});

1. Save the above in vite.config.ts
2. Run npm install, npm run dev
3. Go to https://localhost:4000/
4. Dismiss the error about the self signed certificate (click "Advanced" and "Proceed to localhost")
5. Open Chrome dev tools to check if assets are served with h2 (http2) or http1.1

System Info

System:
    OS: macOS 15.1.1
    CPU: (10) arm64 Apple M2 Pro
    Memory: 1.55 GB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.11.0 - ~/.nvm/versions/node/v22.11.0/bin/node
    Yarn: 4.1.0 - ~/.nvm/versions/node/v22.11.0/bin/yarn
    npm: 10.9.0 - ~/.nvm/versions/node/v22.11.0/bin/npm
    Watchman: 2024.11.04.00 - /opt/homebrew/bin/watchman
  Browsers:
    Chrome: 131.0.6778.86
    Firefox: 128.0
    Safari: 18.1.1
  npmPackages:
    vite: ^6.0.0 => 6.0.0

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[sai-cb]

Before (v5)

After (v6)

[sai-cb]

Updated description and title; This got introduced in 6.0.0-beta.10 and is affecting the stable release.

The 6.0.0-beta.9 release does not seem to include the regression.

[userquin]

Looks like proxy object is empty, we should check with some entry:

[userquin]

proxy should be removed from default server options or check if it has some entry when creating the server, regression here https://github.com/vitejs/vite/pull/18550/files#diff-abb3345b6e3b2ec6d297c2ebc54cca85ae4487a31bac3cc9e78457f5114adb26R1026

[bluwy]

It should be set as undefined by default I believe. Setting an object has intentionally another meaning (regardless of properties) iirc.

[sai-cb]

Tested and confirmed that 6.0.1 does fix the regression, thank you!!!