如何处理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.xx but it doesn't seem to resolve it.

Answer 1

The issue is the circular dependency - monorepo depends on external package that depends back on the monorepo. When trying to resolve it seems to set the monorepo packages as 'null' (so as to defer resolution w/o hanging) and then when it tries to resolve that package it just fails. I don't have a workaround, trying to figure that out for myself.