Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

Current Behavior

In the latest version of NPM (11.12.0), there appears to be a regression with config validation.

This command works in npm@11.10.0 and npm@11.11.0, but fails in npm@11.12.0:

npm install \
  --prefer-offline=true \
  --prefer-online=false \
  --package-lock-only \
  --ignore-scripts \
  --no-audit \
  --no-fund

Error:

Exit prior to config file resolving
cause
--prefer-online cannot be provided when using --prefer-offline

This breaks NPM's git dependency preparation flow, because pacote generates nested install commands with both --prefer-offline=<bool> and --prefer-online=<bool>. I noticed exclusivity was introduced here.

Expected Behavior

If a clean install finds a dependency that triggers the git dependency preparation flow, it should not throw an error from the generated config/flags in pacote.

Steps To Reproduce

1. Using npm@11.12.0
2. Run npm install --prefer-offline=true --prefer-online=false --package-lock-only --ignore-scripts --no-audit --no-fund
3. See error: --prefer-online cannot be provided when using --prefer-offline

Environment

• npm: 11.12.0
• Node.js: 22.22.0
• OS Name: MacOS Tahoe 26.3.1
• System Model Name: Macbook Pro