Allow patch level differences in preflight check

[togakangaroo]

Is this a bug report?

Yes, I am getting an eslint preflight check error hen I don't think I should be.

Did you try recovering your dependencies?

Yes, I've tried deleting the package-lock and rebuilt some stuff, but this issue seems pretty clearcut

Which terms did you search for in User Guide?

I searched for eslint there and in the issues but this is for the new release and I dont' think thats updated yet

Environment

(paste the output of the command here)

Steps to Reproduce

To reproduce

create-react-app craeslint
cd craeslint
npm install eslint@5.6.1

I get the following. I don't think this is correct - a difference in patch version shouldn't cause the preflight check to fail, should it? (Also react-scripts should probably update their eslint version)

> craeslint@0.1.0 test /Users/gmauer/code/craeslint
> react-scripts test


There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix locally.

The react-scripts package provided by Create React App requires a dependency:

  "eslint": "5.6.0"

Don't try to install it manually: your package manager does it automatically.
However, a different version of eslint was detected higher up in the tree:

  /Users/gmauer/code/craeslint/node_modules/eslint (version: 5.6.1) 

Expected Behavior

tests run fine - there is only a difference in patch level of eslint

Actual Behavior

I get the following

> craeslint@0.1.0 test /Users/gmauer/code/craeslint
> react-scripts test


There might be a problem with the project dependency tree.
It is likely not a bug in Create React App, but something you need to fix locally.

The react-scripts package provided by Create React App requires a dependency:

  "eslint": "5.6.0"

Don't try to install it manually: your package manager does it automatically.
However, a different version of eslint was detected higher up in the tree:

  /Users/gmauer/code/craeslint/node_modules/eslint (version: 5.6.1) 

[Timer]

Right now, this is intentional. We want to find an exact version match. We've actually never supported installing ESLint alongside Create React App, so this warning is fine IMO.

For now, please match the version or disable the check with the suggested environment variable.

[gaearon]

@togakangaroo Could you clarify why you're installing ESLint inside your project? Is it for editor integrations or something else?

[schematis]

I'm running into this as well.

The reason I'm installing it is because Yarn doesn't recognize it as being installed in order to satisfy peer dependencies of other packages (ie. eslint-config-airbnb).

[silverwind]

Could you clarify why you're installing ESLint inside your project

In my case, I have it to lint files outside of src. I'd say this check should at least respect semver.

[goncy]

My case is that i use a yeoman generator for copying my usual react lint rules, i can also use this with non-cra projects

[gaearon]

Would allowing patch-level differences for ESLint specifically satisfy most people in this thread?

[gaearon]

Note you can ignore the check (just as it says) by putting

SKIP_PREFLIGHT_CHECK=true

to a file called .env in your project root.

[goncy]

Note you can ignore the check (just as it says) by putting

SKIP_PREFLIGHT_CHECK=true

to a file called .env in your project root.

Yes, my actual solution was adding an .env file with that flag to the generator.

The problem with this is that i think the version mismatch between eslint versions is not that important (maybe i'm wrong), but to solve this problem i add the flag to my .env, maybe doing that i supress another really important warnings. Except for jest, is really important to do this preflight checks for dev dependencies?

[gaearon]

People have definitely complained about broken ESLint before after installing different versions. But yeah patch shouldn’t make a big difference. Although the fact that it even exists up the tree can cause issues by itself.

[togakangaroo]

So to fill in the picture, my own use case is that I have emacs checking my code with eslint. To do this correctly I want it to use the actual version from in my project so I want it to use npx eslint. This means that I have to have it in my project dependencies directly.

I would imagine anyone else who wants to use it in their Dev workflow would have the same. What are the issues that mismatched versions might cause? Is there no way around those?

[Apollo725]

Is there any other way without creating new .env file including 'SKIP_PREFLIGHT_CHECK=true' ?
Error says 'That will permanently disable this message but you might encounter other issues.' so I don't want to face on other issues

[silverwind]

Would allowing patch-level differences for ESLint specifically satisfy most people in this thread?

eslint is a project that follows semver, so minor version differences are compatible too. Suggesting you bark only on major version differences, like for example:

semver.diff(yourVersion, userVersion) === 'major'

[ywwhack]

I have a project which includes both server/client codes.

Project structure like below:

├── README.md
├── config
├── client
├── logs
├── nodemon.json
├── package-lock.json
├── package.json
└── src

Asume server code root path is ProjectRootPath, client code root path is ProjectRootPath/client

When i run npm run build in the client folder, it tell me babel-eslint version conflict with ProjectRootPath/node_modules/babel-eslint, it conflict with my server code root path(not client code root path), is it a bug?