`no-unpublished-require` throws a TypeError when `"."` or `"./"` is required about eslint-plugin-n

[fasttime]

I think the root of the problem is this check where npmignore.match is being called with an argument that is possibly an empty string, resulting in the empty string being passed to ignore that produces the TypeError.

https://github.com/weiran-zsd/eslint-plugin-node/blob/d7b975a07e1b876ca2c75597d054a81564b25685/lib/util/check-publish.js#L52-L54

That's because toRelative returns an empty string when called with an argument that is the same as the package directory. And require('.') resolves to the package directory when called by a file in that location.

This could be probably fixed by making sure that npmignore.match is never called with an empty string. I will try to come up with a test case, and I'll create a PR if my fix works.

[aladdin-add]

sounds it should report an eslint errror in this case - it will throw an 'module not found' error if you run your code.

[fasttime]

Yes, my code doesn't work of course. But the rule should report the linting problem instead of throwing an error.

[aladdin-add]

agreed. just ignoring the case in this rule. we could consider adding a new rule to report requires/imports non-exsistent files.