[bug] flags non-type-only imported type as unknown import

[vegerot]

Version

4.5.11

Reproduction link

https://github.com/vegerot/vue-cli-6320

#3145 (comment)

Environment info

Environment Info:

  System:
    OS: macOS 11.3
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Binaries:
    Node: 15.10.0 - /usr/local/bin/node
    Yarn: 1.22.10 - /usr/local/bin/yarn
    npm: 7.6.0 - /usr/local/bin/npm
  Browsers:
    Chrome: 89.0.4389.47
    Edge: Not Found
    Firefox: 78.8.0
    Safari: 14.1
  npmPackages:
    @types/vue-moment: 4.0.2 => 4.0.2 
    @vue/babel-helper-vue-jsx-merge-props:  1.2.1 
    @vue/babel-helper-vue-transform-on:  1.0.2 
    @vue/babel-plugin-jsx:  1.0.3 
    @vue/babel-plugin-transform-vue-jsx:  1.2.1 
    @vue/babel-preset-app:  4.5.11 
    @vue/babel-preset-jsx:  1.2.4 
    @vue/babel-sugar-composition-api-inject-h:  1.2.1 
    @vue/babel-sugar-composition-api-render-instance:  1.2.4 
    @vue/babel-sugar-functional-vue:  1.2.2 
    @vue/babel-sugar-inject-h:  1.2.2 
    @vue/babel-sugar-v-model:  1.2.3 
    @vue/babel-sugar-v-on:  1.2.3 
    @vue/cli-overlay:  4.5.11 
    @vue/cli-plugin-babel: 4.5.11 => 4.5.11 
    @vue/cli-plugin-e2e-cypress: 4.5.11 => 4.5.11 
    @vue/cli-plugin-eslint: 4.5.11 => 4.5.11 
    @vue/cli-plugin-pwa: 4.5.11 => 4.5.11 
    @vue/cli-plugin-router: 4.5.11 => 4.5.11 
    @vue/cli-plugin-typescript: 4.5.11 => 4.5.11 
    @vue/cli-plugin-unit-jest: 4.5.11 => 4.5.11 
    @vue/cli-plugin-vuex: 4.5.11 => 4.5.11 
    @vue/cli-service: 4.5.11 => 4.5.11 
    @vue/cli-shared-utils:  4.5.11 
    @vue/component-compiler-utils:  3.2.0 
    @vue/eslint-config-standard:  6.0.0 
    @vue/eslint-config-typescript:  7.0.0 
    @vue/preload-webpack-plugin:  1.1.2 
    @vue/test-utils:  1.1.3 
    @vue/web-component-wrapper:  1.3.0 
    eslint-plugin-vue:  7.6.0 
    jest-serializer-vue:  2.0.2 
    js-cookie-vue: 1.0.8 => 1.0.8 
    typescript: 4.1.5 => 4.1.5 (3.9.9)
    vue: 2.6.12 => 2.6.12 
    vue-class-component: 7.2.6 => 7.2.6 
    vue-cli-plugin-moment: 0.1.1 => 0.1.1 
    vue-cli-plugin-vuetify: 2.1.0 => 2.1.0 
    vue-eslint-parser:  7.5.0 
    vue-hot-reload-api:  2.3.4 
    vue-jest:  3.0.7 
    vue-loader:  15.9.6 (16.1.2)
    vue-moment: 4.1.0 => 4.1.0 
    vue-property-decorator: 9.1.2 => 9.1.2 
    vue-router: 3.5.1 => 3.5.1 
    vue-style-loader:  4.1.2 
    vue-template-compiler: 2.6.12 => 2.6.12 
    vue-template-es2015-compiler:  1.9.1 
    vuedraggable: ^2.24.3 => 2.24.3 
    vuetify: 2.4.4 => 2.4.4 
    vuex: 3.6.2 => 3.6.2 
    vuex-class: 0.3.2 => 0.3.2 
  npmGlobalPackages:
    @vue/cli: 4.5.11

Steps to reproduce

Copy/paste the code from #3145 (comment)

Run vue-cli-service serve

What is expected?

Get no warnings in the console

What is actually happening?

---

Please read typescript-eslint/typescript-eslint#3108 (comment) and #3145 (comment)

[LinusBorg]

Copy/paste the code from #3145 (comment)

Asking us to generate a project with your listed dependencies (hopefully with the right options that you chose), copy-paste code (hopefully in the right place, hopefully using dependencies correctly) - that's not a runnable reproduction.

Please respect the issue guidelines and provide a runnable reproduction.

[vegerot]

@LinusBorg apologies. Will do

[vegerot]

Link to reproduction repo: https://github.com/vegerot/vue-cli-6320

@LinusBorg should I make a new issue, or continue using this one?

[vegerot]

@LinusBorg I see you tagged this as "needs team repro". Is there anything I can do to help with that?

[LinusBorg]

that tag means that a team member has to check out your repro. You can only way that someone can pick it up. I won't be able to look into this as I have a few other bases to cover.

[vegerot]

@LinusBorg it's been a few months now and this bug is preventing our team from upgrading ESLint and TypeScript. I'm wondering what I can do to help get this fixed. Do you have a project board where you are tracking the order these issues get completed in?

[LinusBorg]

Hi @vegerot,

thanks for the patience. I couldn't make the time back then to look into it, and thing get drowned out quickly.

I ran your reproduction repository and couldn't reproduce the error/warning in question, neither during serve nor build:

Is there anything special I need to do?

Edit: I was able to get the error switching import type to import. But with import type I don't get any eslint errors.

I also read the discussion in the typescript-eslint repo, but personally can't claim to have fully understood - I don't really use decorators and have zero knowledge about decorator metadata and the intricacies of that.

Do these warnings only happen for the decorators you are using from vuex-class, though? Maybe the issue is to be found there - that lib hasn't been updated in 3 years, maybe something needs to be updated - TS upgrades have a tendency to break stuff even in minor releases as well. Taking into account that this type of problem hasn't been reported by other users of vue-class-component or vue-cli, my suspicion would be in that direction.

If you can help come up with a reproduction that actually demonstrates the problem, and provided that it's only happening for the decorators from @vuex-class, I'd ask you to open an issue there and I'll ping its maintainer, ktsn - he's a team member.

I don't really see an early indication how/where this can be solved on vue-cli's end, as we don't do anything fancy with TS - vue-loader delegates compilation of TS code to the ts-loader and outputs that result as-is. But #3145 shows there are multiple of these instances, though they seem rare (It's hard to judge which scenarios are affected as you are the first person in over 2 years to actually submit a reproduction).

[vegerot]

@LinusBorg let me explain a bit more clearly the issue:

If I use import type, typescript-eslint complains that I should be using import instead.

If I use import, vue-cli complains that export "foo" was not found in 'bar'

[LinusBorg]

I understand that.

But for me, eslint complains when I use import, and doesn't when I use import type:

import:

import type:

...and when using import type, everything builds fine, too, and don't get any eslint warnings when running npm run lint or anything.

So I can't really reproduce the problem with the repo you provided.

[vegerot]

I may need to update eslint in the demo repo

[vegerot]

@LinusBorg my apologies. I have updated the dependencies to reflect the bug