[BUG] npm install --force fails for peerOptional conflicts

[targos]

Current Behavior:

Run npm install --force fails instead of ignoring upstream dependency conflict

Expected Behavior:

It should print a warning and continue with the installation.

Steps To Reproduce:

git clone https://github.com/targos/npm-force-peer-dep.git
cd npm-force-peer-dep
npm install --force

Output:

npm WARN using --force Recommended protections disabled.
npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR! 
npm ERR! Found: typescript@4.1.3
npm ERR! node_modules/typescript
npm ERR!   dev typescript@"^4.1.3" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peerOptional typescript@"^3.2.1" from react-scripts@4.0.1
npm ERR! node_modules/react-scripts
npm ERR!   dev react-scripts@"^4.0.1" from the root project
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR!
npm ERR! See C:\Users\Targos\AppData\Local\npm-cache\eresolve-report.txt for a full report.

npm resolution error report

# npm resolution error report

2021-01-18T07:56:28.615Z

Found: typescript@4.1.3
node_modules/typescript
  dev typescript@"^4.1.3" from the root project

Could not resolve dependency:
peerOptional typescript@"^3.2.1" from react-scripts@4.0.1
node_modules/react-scripts
  dev react-scripts@"^4.0.1" from the root project

Fix the upstream dependency conflict, or retry
this command with --force, or --legacy-peer-deps
to accept an incorrect (and potentially broken) dependency resolution.

Raw JSON explanation object:

{
  "code": "ERESOLVE",
  "current": {
    "name": "typescript",
    "version": "4.1.3",
    "location": "node_modules/typescript",
    "dependents": [
      {
        "type": "dev",
        "name": "typescript",
        "spec": "^4.1.3",
        "from": {
          "location": "D:\\Git\\targos\\npm-force-peer-dep"
        }
      }
    ]
  },
  "edge": {
    "type": "peerOptional",
    "name": "typescript",
    "spec": "^3.2.1",
    "error": "INVALID",
    "from": {
      "name": "react-scripts",
      "version": "4.0.1",
      "location": "node_modules/react-scripts",
      "dependents": [
        {
          "type": "dev",
          "name": "react-scripts",
          "spec": "^4.0.1",
          "from": {
            "location": "D:\\Git\\targos\\npm-force-peer-dep"
          }
        }
      ]
    }
  },
  "peerConflict": null,
  "strictPeerDeps": false,
  "force": true
}

Environment:

• OS: Windows 10
• Node: 15.6.0
• npm: 7.4.3

[targos]

Another one:

git clone https://github.com/targos/npm-workspace-lock.git
cd npm-workspace-lock
git checkout ce69f722ac89990a05bfd8e2f22e81d7a779384a
npm install --force

[Annemike]

I have the same problem but on BigSur

[darcyclarke]

@targos just tried with the latest v7 (7.5.3) & this seems to be resolved - can you try updating & let us know if you're still experiencing issues?

[jpike88]

this is still a problem on 7.5.3 for me. switching back to v6

[isaacs]

This is a legit problem with your dependencies. You can't use react-scripts@4.0.1 and typescript@4.1.3 in the same project, unfortunately, because react-scripts@4.0.1 has an optional peer dependency on typescript@^3.2.1. This is corrected in react-scripts@4.0.2 (which is why it likely worked when @darcyclarke tried it), so it should work fine now.

Nevertheless, it should be ignoring the conflict if --force is used, so that is a bug.

I'm using this package.json to reproduce (note the pinned dependency on react-scripts 4.0.1):

{
  "devDependencies": {
    "react-scripts": "4.0.1",
    "typescript": "^4.1.3"
  }
}