babel-jest dependency issue

[ajm-ska]

A new issue has suddenly appeared on macOS12. None of the ICD tests can run. When they try to run, the following message appears:

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:

  "babel-jest": "^24.9.0"

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

  /Users/acdc/node_modules/babel-jest (version: 27.5.1) 

Manually installing incompatible versions is known to cause hard-to-debug issues.

If you would prefer to ignore this check, add SKIP_PREFLIGHT_CHECK=true to an .env file in your project.
That will permanently disable this message but you might encounter other issues.

To fix the dependency tree, try following the steps below in the exact order:

  1. Delete package-lock.json (not package.json!) and/or yarn.lock in your project folder.
  2. Delete node_modules in your project folder.
  3. Remove "babel-jest" from dependencies and/or devDependencies in the package.json file in your project folder.
  4. Run npm install or yarn, depending on the package manager you use.

In most cases, this should be enough to fix the problem.
If this has not helped, there are a few other things you can try:

  5. If you used npm, install yarn (http://yarnpkg.com/) and repeat the above steps with it instead.
     This may help because npm has known issues with package hoisting which may get resolved in future versions.

  6. Check if /Users/acdc/node_modules/babel-jest is outside your project directory.
     For example, you might have accidentally installed something in your home folder.

  7. Try running npm ls babel-jest in your project folder.
     This will tell you which other package (apart from the expected react-scripts) installed babel-jest.

If nothing else helps, add SKIP_PREFLIGHT_CHECK=true to an .env file in your project.
That would permanently disable this preflight check in case you want to proceed anyway.

P.S. We know this message is long but please read the steps above :-) We hope you find them helpful!

It seems there is a newer version of babel-jest on the system (/Users/acdc/node_modules/babel-jest) and that is conflicting with the older version used by the ICD tests. One solution may be to delete the newer version, however, it might not be the best solution if a user requires the newer dependency for something else.

I have found two working solutions:

1. The .env workaround. When I create a file called .env containing SKIP_PREFLIGHT_CHECK=true, then the ICD tests can run successfully.

2. I have determined that it is our react-scripts dependency that uses babel-jest. Our package.json uses react-scripts version 3.4.4, and that installs babel-jest version 24.9.0. I have tried using the latest react-scripts version which is 5.0.1. That installs babel-jest version 27..5.1 and the error is gone.

@acdo2002 Do you think we should update the react-scripts dependency in our package.json to 5.0.1?