github/core package fails build because of exports map

[43081j]

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.

[marcfehling]

Which version of @actions/core are you using? I believe the packages of the @actions environment introduced some changes that are not backwards-compatible.

I encountered the same issue when moving from @actions/core 2.0.2 to @actions/core 3.0.0. It works fine with 2.0.2 but fails with the exact same error with 3.0.0.

Error: Module not found: Error: Package path . is not exported from package [...]/node_modules/@actions/core (see exports field in [...]/node_modules/@actions/core/package.json)
Did you mean './@actions/core'?
Requests that should resolve in the current directory need to start with './'.
Requests that start with a name are treated as module requests and resolve within module directories (node_modules).
If changing the source code is not an option there is also a resolve options called 'preferRelative' which tries to resolve these kind of requests in the current directory too.
    at [...]/node_modules/@vercel/ncc/dist/ncc/index.js.cache.js:23:2001849
    at [...]/node_modules/@vercel/ncc/dist/ncc/index.js.cache.js:23:389111
    at _done (eval at create ([...]/node_modules/@vercel/ncc/dist/ncc/index.js.cache.js:21:81694), <anonymous>:9:1)
    at eval (eval at create ([...]/node_modules/@vercel/ncc/dist/ncc/index.js.cache.js:21:81694), <anonymous>:34:22)

[43081j]

Yup 3.x here too.

But their exports are correct so it seems like we need to support it somehow it in ncc

[marcfehling]

From the @actions/core changelog:

Breaking change: Package is now ESM-only
CommonJS consumers must use dynamic import() instead of require()

Related pull request: actions/toolkit#2272

[cscnk52]

@marcfehling yes, but it was exist under import * as core from '@github/core', consumers also be ESM.