[BUG] npm install throws "ERR_INVALID_ARG_TYPE" if empty yarn.lock folder is present in root directory.

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

npm install

npm error code ERR_INVALID_ARG_TYPE
npm error The "path" argument must be of type string or an instance of Buffer or URL. Received null
npm error A complete log of this run can be found in: /Users/nparoski/.npm/_logs/2025-11-26T10_05_44_942Z-debug-0.log

Expected Behavior

Expected to install packages without issues.

Steps To Reproduce

1. npm init
2. npm install <package name>
3. mkdir yarn.lock
4. npm install

Environment

• npm: 10.9.0
• Node.js: 22.10.0
• OS Name: MacOS / Ubuntu
• System Model Name: macOS Sequoia / Ubuntu 22
• npm config:

; node bin location = /Users/nparoski/.nvm/versions/node/v22.10.0/bin/node
; node version = v22.10.0
; npm local prefix = /Users/nparoski/projects/npm-test
; npm version = 10.9.0
; cwd = /Users/nparoski/projects/npm-test
; HOME = /Users/nparoski
; Run `npm config ls -l` to show all defaults.```

Start by reproducing the reported sequence with npm init, npm install, an empty yarn.lock directory, and npm install again. Trace how npm install handles the root yarn.lock path, then verify that installation succeeds and add regression coverage for this case.