`import/no-unresolved` on NX monorepos starting from version `3.8.x`

[estiller]

Hi,
Starting from version 3.8.x of eslint-import-resolver-typescript, I started getting import/no-unresolved on references between projects in my NX monorepo with aliases.

It worked fine until version 3.7.0, but it stopped working since. I also tested it on the recently released 3.8.6 but it's still the same issue.

There are some related issues starting from 3.8.x, but this issue wasn't resolved as part of the fixes:

• import-x/no-unresolved errors after updating eslint-import-resolver-typescript from 3.7.0 to 3.8.3 #364
• no-unresolved JS alias regression in 3.8+ #363
• Unable to resolve path to module with aliases. #359

I created a reproduction repo here. It has two libraries, with my-lib2 referencing my-lib.

Reproduction steps:

1. Clone the repository and run pnpm install. This will install version 3.7.0.
2. Run pnpm lint. Everything should work fine.
3. Run pnpm add -D eslint-import-resolver-typescript@3.8.6.
4. Run pnpm lint and you will get a lint error.

   ✖  nx run my-lib2:lint
      > eslint .
      
      
      /Users/eran/estiller/eslint-import-resolver-issue/libs/my-lib2/src/lib/my-lib2.ts
        1:23  error  Unable to resolve path to module '@eslint-import-resolver-issue/my-lib'  import/no-unresolved
      
      ✖ 1 problem (1 error, 0 warnings)

I'd appreciate any help. Thanks!

[JounQin]

Can you helps to try next major version?

#368 (comment)

Although there are some special edge cases failing, but I think most things would just work as expected.

[estiller]

Can you helps to try next major version?

#368 (comment)

Although there are some special edge cases failing, but I think most things would just work as expected.

@JounQin, how can I test it? I don't see a pre-release package on NPM.

[JounQin]

@estiller Did you see the codesandbox ci comment?

https://ci.codesandbox.io/status/import-js/eslint-import-resolver-typescript/pr/368/builds/596603

[estiller]

@JounQin, no, I missed it. 😄

Anyway, it seems to work ok with this version:

pnpm add -D eslint-import-resolver-typescript@https://pkg.csb.dev/import-js/eslint-import-resolver-typescript/commit/1a15b976/eslint-import-resolver-typescript/_pkg.tgz

[JounQin]

@carlocorradini @SukkaW

I think v3.8+ bug fix at #345 brings more headaches than imagination, I'd like to revert back and leave the rest in next major rewrite at #368, what do you think?

[JounQin]

@JounQin, no, I missed it. 😄

Anyway, it seems to work ok with this version:

pnpm add -D eslint-import-resolver-typescript@https://pkg.csb.dev/import-js/eslint-import-resolver-typescript/commit/1a15b976/eslint-import-resolver-typescript/_pkg.tgz

@estiller Great to hear, did you notice any performance improvement?

[estiller]

@estiller Great to hear, did you notice any performance improvement?

I just tried it on the "real" project, and on my local machine, it got the total lint time from ~15 seconds to ~13 seconds, which is a sizeable improvement given that we have other plugins we use as well.

[jmeinlschmidt]

same issue here, after downgrading to v3.7.0, the problem dissapears

[carlocorradini]

I know the problem, etc...
I'll send an update ASAP

[carlocorradini]

We have a subtle issue:
The root file eslint.config.mjs specifies the project as ./tsconfig.base.json. Each library has its own eslint.config.mjs file, which is an exact copy of the root file. The project is defined as tsconfig.base.json and is identical to the root. However, because the latter file is not present in each library directory, we fall back to reading the file tsconfig.json. The initialization of mappers is empty (ignored as we found 0 TypeScript files due to files: [] and include: []) because we do not currently support references (until the next major release), and as a result, we are unable to resolve the path.
A simple and effective solution:

--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -62,7 +62,7 @@ export default [
       ],
     },
     settings: {
-      'import/resolver': { typescript: { project: './tsconfig.base.json' } },
+      'import/resolver': { typescript: { project: './tsconfig.lib.json' } },
     },
   },
 ];

The paths are mapped correctly in PR #368 because it adds support for project references, so all linked/referenced `tsconfig.json are detected and mapped.
Nonetheless, we need to make a simple change and delete

eslint-import-resolver-typescript/src/index.ts

Line 507 in 7fdfd80

if (files.length === 0) {

In PR #372, we added the ability to search for a path across all mappers if the current file is unknown. Therefore, even though the files are empty, we still need to add the mapper. The latter not only adds a minifx for #372, but it also allows your repro to work correctly (even if it's incorrect... amazing luck!)

[estiller]

I can confirm that version 3.8.7 fixes this issue. Thank you so much!