[BUG] npm7 does not create transitive node_module folders for dependencies referenced via file:/

[mattem]

I've searched release notes, however I was unable to see if this was an intended breaking change.

Current Behavior:

When referencing a dependency via file:../path/to/dep, npm@7.0.9 does not install or create the transitive node_modules folder for dep

Expected Behavior:

npm@6.12.0 will create and install the node_modules folder for the referenced dependency

Steps To Reproduce:

mkdir a b

// create the package.json files with dependencies
cat << EOF > b/package.json
{
  "name": "b",
  "version": "1.0.0",
  "dependencies": {
    "lodash": "^4.17.20"
  }
}
EOF

cat << EOF > a/package.json
{
  "name": "a",
  "version": "1.0.0",
  "dependencies": {
    "b": "file:../b"
  }
}
EOF

// create a lock file for b
cd b
npm install --package-lock-only

// install for a, creating lock file and node_modules
cd ../a
npm install

a/node_modules will contain the symlink to ../../b, but with no node_modules for b

Environment:

npm@7:

• OS: MacOS 10.14.4
• Node: v15.0.1
• npm: v7.0.9

npm@6:

• OS: MacOS 10.14.4
• Node: v12.13.0
• npm: v6.12.0

[darcyclarke]

@mattem we are aware of this as a breaking change between v6 & v7 - we're going to consider this as a larger topic as to whether to change back this behavior in the next Open RFC call. As a point of reference, linked deps that are a child of the root will actually be installed fully, whereas if they're linked outside they aren't today (again, as you've seen).

I'll circle back on this when we have an update from the call next Wednesday