How to check pnpm strict-peer-dependencies (ERR_PNPM_PEER_DEP_ISSUES) when "Lockfile is up to date"?

Question

When I add dependency without it's peerDependency in empty project by editing package.json like:

{
  "name": "pnpmtest",
  "devDependencies": {
    "eslint-plugin-jsx-a11y": "^6.6.0"
  }
}

and then run

pnpm install

Command will output error ERR_PNPM_PEER_DEP_ISSUES

devDependencies:
+ eslint-plugin-jsx-a11y 6.6.1

 ERR_PNPM_PEER_DEP_ISSUES  Unmet peer dependencies

.
└─┬ eslint-plugin-jsx-a11y 6.6.1
  └── ✕ missing peer eslint@"^3 || ^4 || ^5 || ^6 || ^7 || ^8"
Peer dependencies that should be installed:
  eslint@"^3 || ^4 || ^5 || ^6 || ^7 || ^8"

Above command output 1 exit code.

echo $?
1

This error is perfectly fine since my project is missing eslint. This is desired output.

My problem starts in CI environment where I would also like to see this error after pnpm install and break CI pipeline. Currently when I remove node_modules and run above install once again (this is simulation what is happening in CI) I do not see error and command output code 0.

→ rm -rf node_modules

→ pnpm install
Lockfile is up to date, resolution step is skipped
Packages: +56
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Packages are hard linked from the content-addressable store to the virtual store.
  Content-addressable store is at: /Users/mjanaszek/Library/pnpm/store/v3
  Virtual store is at:             node_modules/.pnpm
Progress: resolved 56, reused 56, downloaded 0, added 56, done

devDependencies:
+ eslint-plugin-jsx-a11y 6.6.1

→ echo $?
0

How to check in CI environment (when "Lockfile is up to date") if my dependencies contains some ERR_PNPM_PEER_DEP_ISSUES?

Answer 1

This command does the trick:

pnpm install --resolution-only

The help for --resolution-only says:

Re-runs resolution: useful for printing out peer dependency issues

Not a very self explanatory name but does what you needed (and what I needed too!)