vercel/ncc

github/core package fails build because of exports map

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#1,311 建立於 2026年3月15日

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 (5 留言) (5 反應) (0 負責人)JavaScript (8,841 star) (273 fork)batch import
bughelp wanted

描述

The @github/core package has the following exports:

  "exports": {
    ".": {
      "types": "./lib/core.d.ts",
      "import": "./lib/core.js"
    }
  }

In a project which has type: "module", and simply import * as core from '@github/core', we get the following error:

ncc: Version 0.38.4 ncc: Compiling file index.js into ESM ncc: Using typescript@5.9.3 (local user-provided) Error: Module not found: Error: Package path . is not exported from package /code/node_modules/@actions/core (see exports field in /code/node_modules/@actions/core/package.json) Did you mean './@actions/core'?

im guessing this is because whatever throws this error is looking for a default export rather than import. or it is mistakenly looking up the non-existent CJS entrypoint.

im not sure what dependency of ncc throws this error so i haven't managed to debug it myself.

貢獻者指南

技術棧
javascripttypescriptnodejs
領域
build systemtooling
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
預計時間有經驗貢獻者完成調查、實作、測試並準備 pull request 的粗略時間範圍。
1-3 hours
活動狀態議題目前的可參與程度：新鮮、活躍、陳舊、阻塞或等待維護者輸入。
active
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
needs investigation
前置要求
Understanding of Node.js module resolutionFamiliarity with package.json exports fieldKnowledge of ncc internals
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
30
研究方向
The issue is that ncc fails to resolve a package with a conditional exports map that only provides an 'import' condition. The error suggests ncc is looking for a default or CJS entrypoint. Investigate how ncc resolves module paths, specifically in src/index.js or lib/ directory. Check how ncc handles the 'exports' field and 'type: module' in package.json. Look for any existing tests related to ESM bundling. Also examine the upstream dependency that throws the 'Module not found' error chain.