[smaugho]

Fixes #23752.

Problem

In a pnpm workspace, installing the node package for a target only installed that package's own dependencies. When the package depends on another workspace package, that package's dependencies were left uninstalled, so code importing through it failed at runtime (e.g. Cannot find package '@invented/leaf').

Change

When Pants installs a pnpm workspace member, it now selects the member together with its dependencies, using pnpm's <package>... filter, instead of the member alone.

• Only the pnpm install path changes. Ordinary commands, npm and yarn, root environments and single-package projects keep their current selectors.
• Release note added in docs/notes/2.34.x.md.

Tests

• New regression test: a workspace reader -> contract -> leaf. It installs through the real rules and runs Node. On current main without the fix it fails (Cannot find package '@invented/leaf'); with the fix Node prints 42.
• Scope cases cover installation versus ordinary commands across pnpm, npm and yarn, and member, root and single environments.
• Verified on main 05181fa with the native engine built locally: 25/25 tests in install_node_package_test.py and nodejs_project_environment_test.py, lint, MyPy, build-support/githooks/pre-push and pants --changed-since=HEAD fmt all pass.

AI disclosure

This PR was written primarily by Claude Code; I reviewed and tested it.

[benjyw]

Thanks for the contribution. We've just branched for 2.34.x, so merging this pull request now will come out in 2.35.x, please move the release notes updates to docs/notes/2.35.x.md if that's appropriate.

[smaugho]

Moved the release note to 2.35.x. docs/notes/2.35.x.md didn't exist on main yet, so I created it from the release-notes template; happy to rebase onto the CI-generated file instead if you prefer (once it is available).

[benjyw]

Ah whoops! The 2.35.x release notes are now on main, if you could add your note to that. Thanks!

I'm not really qualified to review, as I know precious little about the node ecosystem, but I'll try unless @tobni can jump in.

[benjyw]

Looks good to me, modulo one nit (and the notes merge)

[benjyw]

It looks like we encapsulate package manager-specific logic in PackageManager, so maybe this logic should live there too? Something like workspace_dependencies_suffix?