v10.3.1

Fixed

• Fixed 502 responses for proxied dev server assets under rack-proxy v1. PR #1222 by jcbpl. Fixes #1220.
• Fixed dev-server liveness checks treating refused macOS 27 connections as running. The Ruby probe now verifies the connected socket's SO_ERROR result before proxying asset requests, avoiding false-positive dev-server detection and resulting 502 responses. PR #1225 by justin808. Fixes #1224.
• Fixed webpack Babel, SWC, and esbuild rules skipping explicitly included .cjs files. PR #1219 by oiahoon. Fixes #1218.
• Added a shakapacker:doctor warning for Rspack React Refresh v2 configs that still use the v1 default-export constructor pattern. PR #1207 by justin808. Existing configs with const ReactRefreshPlugin = require("@rspack/plugin-react-refresh") followed by new ReactRefreshPlugin() can fail after upgrading to @rspack/plugin-react-refresh v2 with ReactRefreshPlugin is not a constructor; Doctor now points to the affected JS/TS config file and suggests the named-export/default/module compatibility form. Fixes #1204.
• Fixed the missing-@babel/core failure to report an actionable install message. PR #1212 by justin808. Babel-transpiled builds whose app lacks @babel/core previously surfaced a raw module-resolution error from the Babel 8 compatibility check; the rule now explains which package to install and how to switch javascript_transpiler instead. Refs #1163.

Documentation

• Documented the required css-loader@^7.1.4 in the v10 Rspack upgrade instructions. PR #1211 by justin808. The v10 upgrade guide's copy-paste Rspack v2 commands omitted css-loader, so apps following them could upgrade into an unsatisfied peer dependency.