[BUG][Regression] ERESOLVE if peerDependencies of dependencies support later major version

[kevinoid]

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

With npm@^7.20.3 or [email protected], when one of the peer dependencies of a dependency includes a later major version than the dependency version (in addition to the same major version), npm install --strict-peer-deps=true fails with ERESOLVE, as described in issue #2055.``

Expected Behavior

npm install should complete successfully with the latest version declared by the dependency (which also satisfies the peer dependency of the other dependency).

Steps To Reproduce

Using the same steps as #2055:

With package.json:

{
  "name": "project-a",
  "dependencies": {
    "webpack": "^4.41",
    "webpack-dev-server": "^3.9"
  }
}

Running npm install --strict-peer-deps=true produces:

npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR! 
npm ERR! While resolving: [email protected]
npm ERR! Found: [email protected]
npm ERR! node_modules/webpack
npm ERR!   webpack@"^4.41" from the root project
npm ERR!   peer webpack@"^4.0.0 || ^5.0.0" from [email protected]
npm ERR!   node_modules/webpack-dev-server
npm ERR!     webpack-dev-server@"^3.9" from the root project
npm ERR!   1 more (terser-webpack-plugin)
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! webpack-dev-middleware@"^3.7.2" from [email protected]
npm ERR! node_modules/webpack-dev-server
npm ERR!   webpack-dev-server@"^3.9" from the root project
npm ERR! 
npm ERR! Conflicting peer dependency: [email protected]
npm ERR! node_modules/webpack
npm ERR!   peer webpack@"^4.0.0 || ^5.0.0" from [email protected]
npm ERR!   node_modules/webpack-dev-middleware
npm ERR!     webpack-dev-middleware@"^3.7.2" from [email protected]
npm ERR!     node_modules/webpack-dev-server
npm ERR!       webpack-dev-server@"^3.9" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR! 
npm ERR! See /home/user/.cache/npm/eresolve-report.txt for a full report.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/user/.cache/npm/_logs/2021-10-09T21_37_39_782Z-debug.log

I would expect it to install [email protected], since it is the latest version which satisfies the webpack@^4.41 dependency and it also satisfies the webpack@"^4.0.0 || ^5.0.0" peer dependency from [email protected].

Environment

• OS: Debian GNU/Linux testing
• Node: v12.22.5
• npm: npm@^7.20.3 or [email protected]

I believe I've bisected the regression to 97cb5ec which upgraded to @npmcli/[email protected] for #3377.

[kevinoid]

Another example:

package.json:

{
  "name": "project-a",
  "dependencies": {
    "eslint": "^7.0.0",
    "eslint-plugin-node": "^11.0.0"
  }
}

npm install --strict-peer-deps=true

npm ERR! code ERESOLVE
npm ERR! ERESOLVE could not resolve
npm ERR! 
npm ERR! While resolving: [email protected]
npm ERR! Found: [email protected]
npm ERR! node_modules/eslint
npm ERR!   eslint@"^7.0.0" from the root project
npm ERR!   peer eslint@">=5.16.0" from [email protected]
npm ERR!   node_modules/eslint-plugin-node
npm ERR!     eslint-plugin-node@"^11.0.0" from the root project
npm ERR! 
npm ERR! Could not resolve dependency:
npm ERR! eslint-plugin-es@"^3.0.0" from [email protected]
npm ERR! node_modules/eslint-plugin-node
npm ERR!   eslint-plugin-node@"^11.0.0" from the root project
npm ERR! 
npm ERR! Conflicting peer dependency: [email protected]
npm ERR! node_modules/eslint
npm ERR!   peer eslint@">=4.19.1" from [email protected]
npm ERR!   node_modules/eslint-plugin-es
npm ERR!     eslint-plugin-es@"^3.0.0" from [email protected]
npm ERR!     node_modules/eslint-plugin-node
npm ERR!       eslint-plugin-node@"^11.0.0" from the root project
npm ERR! 
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --no-strict-peer-deps, --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.
npm ERR! 
npm ERR! See /home/user/.cache/npm/eresolve-report.txt for a full report.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/user/.cache/npm/_logs/2021-10-09T21_57_04_502Z-debug.log

[lukekarrys]

Thanks for the thorough report @kevinoid! This is the same issue as #3881, but manifesting in that ERESOLVE error when --strict-peer-deps is turned on. The good news is that the fix for that works for this as well. I pulled in npm/arborist#337 and was able to run both your examples successfully now. This fix should go out tomorrow!

{
  "dependencies": {
    "eslint": "^7.0.0",
    "eslint-plugin-node": "^11.0.0"
  }
}

❯ npm i --strict-peer-deps=true
❯ npm ls eslint
[email protected] /Users/lukekarrys/Desktop/npm-sandbox/3868
├─┬ [email protected]
│ ├─┬ [email protected]
│ │ └── [email protected] deduped
│ └── [email protected] deduped
└── [email protected]

{
  "dependencies": {
    "webpack": "^4.41",
    "webpack-dev-server": "^3.9"
  }
}

❯ npm i --strict-peer-deps=true
❯ npm ls webpack
[email protected] /Users/lukekarrys/Desktop/npm-sandbox/3868
├─┬ [email protected]
│ ├─┬ [email protected]
│ │ └── [email protected] deduped
│ └── [email protected] deduped
└─┬ [email protected]
  └─┬ [email protected]
    └── [email protected] deduped

[kevinoid]

Interesting! Thanks for investigating an implementing a fix @lukekarrys! I'll look forward to it in a future release.