Fix language-negotiation redirect when visiting language-prefixed paths | Dev Logs

Date: 2026-01-11 15:00 Summary: Fix language-negotiation redirect when visiting language-prefixed paths

[question] http://localhost:8787/ja/ 下，点击http://localhost:8787/ja/tools/website-headers ，结果跳转 http://localhost:8787/zh/ja/tools/website-headers ，显示404 Not Found

[try to solve] Problem: The middleware that performs language negotiation treated a path like /ja/... as non-explicit when ja was not in the SITE_LANGS enabled list. That caused the middleware to prefix the picked language (e.g. zh) onto the existing path, producing /zh/ja/... and a 404.

Fix: Treat any supported language code in the path as an explicit prefix (do not require it to be present in SITE_LANGS for this detection). This prevents the middleware from performing language-negotiation redirects for explicitly language-prefixed URLs.

Actions:

• Modified src/index.ts:
  • Changed getExplicitLangFromPath to only check isSupportedLang(seg) and not enabled.includes(seg).

Notes:

• The route handlers still use SITE_LANGS to decide which language to render or fall back to the default when necessary. The change only prevents accidental double-prefix redirects.