[mpelikan]

With no lockfile and no root node_modules, a workspace has no Link yet, so the missing-edge walk in #initTree never reaches the packages already installed under it. Their missing dependencies are never queued, and npm install exits 0 with an incomplete tree and lockfile.

This makes the walk also descend from each workspace's edges when it visits the project root. It walks into what the workspace has installed rather than the workspace itself: queueing the workspace there, ahead of the root, bypasses the workspaces filter and changes hoisting (it breaks the filtered-reification tests in reify.js).

This overlaps #9985, which changes the same walk to follow workspace links. Neither depends on the other: #9985 covers the case where the link exists, this one the case where it does not. Whichever lands second needs a small rebase.

Checked locally on 7b50811:

• the reproduction in [BUG] Dependencies of packages under a workspace's node_modules are dropped when the root node_modules and lockfile are deleted #10011 now installs a complete tree, also with --install-strategy=linked and --workspace=a
• the new test fails without the change and passes with it
• workspaces/arborist: all tests pass with coverage at 100%, lint clean
• root suite: the same 15 files fail on my machine with and without this change

Fixes #10011