Extensionless require() for subpath in package with subpath folder mappings in its exports map fails to resolve

[tbroyer]

• Rollup Plugin Name: node-resolve, commonjs
• Rollup Plugin Version: node-resolve=11.2.1, commonjs=18.0.0
• Rollup Version: 2.45.2
• Operating System (or Browser): Arch Linux
• Node Version: v15.14.0
• Link to reproduction (⚠️ read below): https://replit.com/@tbroyer/rollup-plugin-repro-issue-865

Expected Behavior

Extensionless subpath require()s, from a package with a subpath folder mappings for that subpath, resolves the file by appending the extension.

Actual Behavior

Error: Could not load /home/runner/rollup-plugin-repro/node_modules/extract-files/public/extractFiles (imported by input.js): ENOENT: no such file or directory, open '/home/runner/rollup-plugin-repro/node_modules/extract-files/public/extractFiles'

Additional Information

Copied from #684 (comment):

Following https://nodejs.org/api/modules.html#modules_all_together, require("extract-files/public/extractFiles") will end up calling

PACKAGE_EXPORTS_RESOLVE("file:///…/node_modules/extract-files", "./public/extractFiles", { …, "./public/": "./public/", … }, ["node", "require"])

Following https://nodejs.org/api/esm.html#esm_resolver_algorithm_specification, this will call

PACKAGE_IMPORTS_EXPORTS_RESOLVE("./public/extractFiles", { …, "./public/": "./public/", … }, "file:///…/node_modules/extract-files", false, ["node", "require"])

which will then call (from 3.2.3)

PACKAGE_TARGET_RESOLVE("file:///…/node_modules/extract-files", "./public/", "extractFiles", false, false, ["node, "require"])

This will return (from 1.8) file:///…/node_modules/extract-files/public/extractFiles. PACKAGE_EXPORTS_RESOLVE will thus return { resolved: "file:///…/node_modules/extract-files/public/extractFiles", exact: false }.
Back to https://nodejs.org/api/modules.html#modules_all_together, we'll end up in

RESOLVE_ESM_MATCH({ resolved: "file:///…/node_modules/extract-files/public/extractFiles", exact: false })

and because of exact: false, Node would correctly add the .js extension and find file:///…/node_modules/extract-files/public/extractFiles.js.

Webpack 5 had the same issue, and changed behavior last October: webpack/enhanced-resolve#256

So, this is a combination of using node-resolve, commonjs, extensionless requires, and a package using the deprecated subpath folder mappings. Had the extract-files package used subpath patterns, it would have ended up in RESOLVE_ESM_MATCH with exact: true, making the file extension mandatory.

[stale]

Hey folks. This issue hasn't received any traction for 60 days, so we're going to close this for housekeeping. If this is still an ongoing issue, please do consider contributing a Pull Request to resolve it. Further discussion is always welcome even with the issue closed. If anything actionable is posted in the comments, we'll consider reopening it. ⓘ