[Feature request] import/no-same-package-import

[Nantris]

Refactoring some code today in a package called 'our-utils' I noticed one of the files in that package was importing like:

import { someDep } from 'our-utils';

Now in reality, someDep was in a file adjacent to the one we were working in, and the optimal import would be, in my view:

import { someDep } from '.';

Is there any rule already that does this? I don't think so, but maybe I overlooked one. This would be like the import/no-self-import rule, but working on entire packages rather than single files.

[ljharb]

There is already a rule - https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-useless-path-segments.md - but if you're using a custom alias, i'm not sure how well it will function.

[Nantris]

We're using that rule, but it doesn't have any effect with monorepo packages that I can see. It seems to only affect relative imports. We're not using any custom aliasing for the package in question, neither via Webpack nor Babel.

[ljharb]

Why would it be possible to import something by both a relative path and a bare specifier??

[Nantris]

I'm not sure I understand the question. Packages' files can import from the package they belong to, by the package name, even if that's highly inadvisable. The line in question surely came about during a refactor and was simply overlooked.

So with a structure like:

 some-package
   index.js
   A.js
   B.js (contains the dependency `someDep`)

If some-package/index.js re-exports all the named exports of A and B then if you do import { someDep } from 'some-package' in A, it will import the relevant dependency from index.js. This is probably never what someone intends as it's highly inadvisable, but it's certainly possible.

[ljharb]

If you're talking about node's new "self import" feature, yes, but that's only supported in node 12.17+ and 13+ (https://github.com/inspect-js/has-package-self-reference), and it's not yet supported in resolve - which means it's not yet supported in this plugin.

[Nantris]

Hmmm... I wish I'd noted down the affected file name so I could go back through git blame and say for sure whether this predates our upgrade to Node 12.x. The file has probably been like that for a long while before I discovered it the other day - but I'm guessing it must have occurred just after we started using Node 12.x.

When it becomes possible to add this rule, I think it would be valuable.