How to deal with NPM error: Cannot set properties of null (setting 'parent')?

Question

This NPM error happens when used in a monorepo with NPM workspaces feature. I have a monorepo with 5 packages: a, b, c, d and e. I also have a package in a different repository which is not a workspace. The name of that package is x and it depends on package c and d.

The problem happens when I try to add package x as a dependency for my package e. Every time I try: npm install x -w packages/e, I get following error:

npm ERR! Cannot set properties of null (setting 'parent')

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/harshal/.npm/_logs/2022-11-11T17_27_57_008Z-debug-0.log

There is absolutely nothing in the error log except the fact that the error originates in arborist package when resolving dependencies.

I have tried using multiple NPM versions ^8.x.x but it doesn't seem to resolve it.

Answer 1

I've seen this happen when you're trying to run npm i from the wrong location.

Just double check that you are actually running at the same location your package.json file is located.