[BUG] TypeError: Cannot read property 'length' of undefined

[simllll]

Current Behavior:

If I install my monorepo with lerna bootstrap, it fails with

6917 warn ERESOLVE overriding peer dependency
6918 timing idealTree Completed in 236624ms
6919 timing command:install Completed in 236632ms
6920 verbose stack TypeError: Cannot read property 'length' of undefined
6920 verbose stack     at explainDependents (/usr/local/lib/node_modules/npm/lib/utils/explain-dep.js:68:19)
6920 verbose stack     at explainNode (/usr/local/lib/node_modules/npm/lib/utils/explain-dep.js:13:3)
6920 verbose stack     at explainEresolve (/usr/local/lib/node_modules/npm/lib/utils/explain-eresolve.js:24:24)
6920 verbose stack     at explain (/usr/local/lib/node_modules/npm/lib/utils/explain-eresolve.js:64:38)
6920 verbose stack     at EventEmitter.log.warn (/usr/local/lib/node_modules/npm/lib/utils/setup-log.js:20:23)
6920 verbose stack     at Arborist.[warnPeerConflict] (/usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/build-ideal-tree.js:1039:14)
6920 verbose stack     at Arborist.[placeDep] (/usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/build-ideal-tree.js:1105:32)
6920 verbose stack     at Arborist.[placeDep] (/usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/build-ideal-tree.js:1216:41)
6920 verbose stack     at /usr/local/lib/node_modules/npm/node_modules/@npmcli/arborist/lib/arborist/build-ideal-tree.js:767:46
6920 verbose stack     at Array.map (<anonymous>)
6921 verbose cwd /home/simon/Dev/hokify/hokify-frontend
6922 verbose Linux 5.4.0-52-generic
6923 verbose argv "/usr/local/bin/node" "/usr/local/bin/npm" "install"
6924 verbose node v14.15.0
6925 verbose npm  v7.0.7
6926 error Cannot read property 'length' of undefined
6927 verbose exit 1

Expected Behavior:

should just install everything

Steps To Reproduce:

Kinda hard to say, it's only happening in my monorepo right now, where I had to add some (non needed) react dependecies to solve some peer dependencies issues with storybook.

Environment:

Os: Ubuntu 20.04
Node: 14.15.0
npm: 7.0.7

[ljharb]

Can you try with npm v7.0.8?

[simllll]

Nice, seems to solve my issue! Thanks

[brent-hoover]

Still see this error with npm v. 7.0.8 using lerna

[ljharb]

@zenweasel upgrade to v7.0.13 and try?