Package subpath './lib' is not defined by "exports"

[aplr]

I just ran npm update, which updated headers-polyfill to the just released 3.1.0, which modifies the exports in package.json. This is the error I get:

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './lib' is not defined by "exports" in /myapp/node_modules/headers-polyfill/package.json
    at new NodeError (node:internal/errors:387:5)
    at throwExportsNotFound (node:internal/modules/esm/resolve:464:9)
    at packageExportsResolve (node:internal/modules/esm/resolve:748:3)
    at resolveExports (node:internal/modules/cjs/loader:493:36)
    at Function.Module._findPath (node:internal/modules/cjs/loader:533:31)
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:942:27)
    at Function.Module._load (node:internal/modules/cjs/loader:804:27)
    at Module.require (node:internal/modules/cjs/loader:1028:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (/myapp/node_modules/@mswjs/interceptors/lib/interceptors/ClientRequest/NodeClientRequest.js:89:13) {
  code: 'ERR_PACKAGE_PATH_NOT_EXPORTED'
}

[jtoar]

I work on RedwoodJS and our CI just ran into the same thing: https://github.com/redwoodjs/redwood/actions/runs/3059432181/jobs/4936841173#step:8:1264

We use MSW in the context of Storybook so the stack trace is a bit different, but the initial error is the same:

ModuleNotFoundError: Module not found: Error: Package path ./lib is not exported from package /Users/dom/prjcts/smoke-test-debug/node_modules/headers-polyfill (see exports field in /Users/dom/prjcts/smoke-test-debug/node_modules/headers-polyfill/package.json)
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/Compilation.js:2016:28
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/NormalModuleFactory.js:798:13
    at eval (eval at create (/Users/dom/prjcts/smoke-test-debug/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:10:1)
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/NormalModuleFactory.js:270:22
    at eval (eval at create (/Users/dom/prjcts/smoke-test-debug/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:9:1)
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/NormalModuleFactory.js:434:22
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/NormalModuleFactory.js:116:11
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/NormalModuleFactory.js:670:25
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/NormalModuleFactory.js:855:8
    at /Users/dom/prjcts/smoke-test-debug/node_modules/webpack/lib/NormalModuleFactory.js:975:5

Downgrading to 3.0.10 fixes it.

[aplr]

It's an issue within mswjs/interceptors, therefore I've moved the issue to mswjs/interceptors#285

[kettanaito]

Thanks for reporting this. I've opened a fix at mswjs/interceptors#286. Will publish today.