No useful error provided when importing json array file without @rollup/plugin-json

[hannessolo]

Rollup Version

^2.78.0

Operating System (or Browser)

MacOS 12.2.1

Node Version (if applicable)

No response

Link To Reproduction

https://stackblitz.com/edit/node-krh8ki?file=README

Expected Behaviour

When requireing a json file, the plugin @rollup/plugin-json is required.

If the plugin is missing, I would expect to get the message Error: Unexpected token (Note that you need @rollup/plugin-json to import JSON files) - as a new user, this is an extremely helpful error message.

Actual Behaviour

When requireing a json file that has an array as the root, and not an object, this error message is not displayed - instead, a much less useful message Error: 'default' is not exported by json-array.json, imported by /home/projects/node-krh8ki/json-array.json?commonjs-proxy is shown.

[lukastaegert]

An empty array is valid JavaScript, so it is slightly tricky to detect this. But I guess to improve here, it would be sufficient to extend the errors for missing exports with a check if the file extension is .json and then add the same hint to those error messages.
Glad you like the hint we added to the parse error 😉

[rollup-bot]

This issue has been resolved via #4741 as part of rollup@3.7.1. You can test it via npm install rollup.