@open-wc/building-rollup fails to recognize the package.json exports field

[eKoopmans]

Expected behavior

Rollup (using config from @open-wc/building-rollup) should be able to build projects that include dependencies using subpath exports, and more generally the exports field.

Actual Behavior

When a project attempts to import from a dependency that uses subpath exports:

• if the subpath exactly matches the actual location in the repo (e.g. "./src/submodule.js": "./src/submodule.js"), it works fine
• otherwise, the dependency is not found:

  Error: 'example/file.js' is imported by src/index.js, but could not be resolved – treating it as an external dependency

This indicates the exports field in package.json is being ignored entirely.

Additional context

The solution is to upgrade @rollup/plugin-node-resolve to its latest version.

We are using @open-wc/building-rollup v1.10.0, but the issue is still present in v2. It's caused by using an old version of @rollup/plugin-node-resolve, which is set to ^7.1.1. We have resolved the issue on our end by explicitly adding the latest @rollup/plugin-node-resolve (v13.3.0) to our Rollup config, and setting nodeResolve: false in building-rollup.

Some discussion on Rollup's support of the exports field: rollup/plugins#208.

[web-padawan]

Updated @rollup/plugin-node-resolve to v13 in #2192 and released in @open-wc/building-rollup 2.2.0. Closing.