fix(exec): resolve workspace-local bin under the linked install strategy

[manzoorwanijk]

In continuation of our exploration of using install-strategy=linked in the Gutenberg monorepo, which powers the WordPress Block Editor.

Under install-strategy=linked, npm exec -w <ws> -- <bin> ignored a workspace-local bin (provided by a sibling workspace dependency) and fell through to the registry, producing a spurious E404. The hoisted strategy ran the local bin correctly.

Why

For a workspace exec, the command computed the local bin directory as resolve(this.npm.localDir, name, 'node_modules', '.bin'), i.e. <root>/node_modules/<name>/node_modules/.bin. That path only resolves when the workspace is symlinked into the root node_modules as <name>, which is how the hoisted strategy lays workspaces out. The linked strategy does not hoist workspaces into the root node_modules; the workspace's real bin lives at <workspace>/node_modules/.bin. libnpmexec walks up from the given bin directory looking for node_modules/.bin/<bin>, so starting from the nonexistent hoisted path never reached the workspace's actual bin and the lookup fell back to the registry.

How

Base the local bin directory on the workspace's own path (runPath) instead of the hoisted localDir/<name> location. This is correct under both strategies: linked finds the bin in the workspace's node_modules/.bin, and hoisted still finds the root-hoisted bin because the walk-up continues from the workspace directory to the root node_modules/.bin.

References

Fixes #9616

[manzoorwanijk]

The coverage is broken in latest as well.

EDIT: Resolved by #9646

[github-actions]

🎉 Backport to release/v11 created: #9648