Feature Request: Trust lockfile for vendored pnpm deployments #978

Context

When deploying a Node.js application to Cloud Foundry using pnpm deploy (non-legacy mode),
the generated pnpm-lock.yaml in the deploy directory records tarball URLs from the private
registry used during the CI build (e.g. GitHub Packages, Nexus, Artifactory, etc.).

When the buildpack runs pnpm rebuild --recursive (which is OK),
pnpm re-verifies every lockfile entry against the public registry (registry.npmjs.org).
This fails with:

ERR_PNPM_TARBALL_URL_MISMATCH

because the tarball URLs in the lockfile point to the private registry, not to npmjs.org.

This affects any project that uses a private registry (GitHub Packages, Nexus, Artifactory,
etc.), vendors dependencies via pnpm deploy, and deploys to Cloud Foundry.

Discussion

Option A — --trust-lockfile by default for vendored deployments

In pnpm.go, pass --trust-lockfile to pnpm rebuild whenever IsVendored == true:

cmd := exec.Command("pnpm", "rebuild", "--recursive", "--trust-lockfile")

Rationale: The logic is consistent with the intent of #964 itself. If the buildpack
already trusts node_modules/ enough to skip the install phase, it should equally trust
the lockfile that produced those node_modules/. A vendored deployment is by definition
a pre-audited artifact — the trust boundary is the zip, not the staging container.

Drawback: It removes supply-chain re-verification unconditionally for all vendored
deployments, which may not be desirable for all users.

Option B — Opt-in via environment variable

Introduce a NODE_PNPM_TRUST_LOCKFILE=true environment variable that the user can set
on their CF application when using a private registry:

if os.Getenv("NODE_PNPM_TRUST_LOCKFILE") == "true" {
    cmd := exec.Command("pnpm", "rebuild", "--recursive", "--trust-lockfile")
} else {
    cmd := exec.Command("pnpm", "rebuild", "--recursive")
}

Set it in manifest.yml or MTA descriptor:

env:
  NODE_PNPM_TRUST_LOCKFILE: "true"

Rationale: The buildpack is a generic tool used across many different projects and
organisations. Making trust opt-in keeps the default conservative and lets each team
make an explicit, reviewable decision. The environment variable is visible in the
application manifest, making it auditable.

Summary

We would be happy to contribute a PR for whichever approach the maintainers prefer.

Related

• Add pnpm package manager support #942 — Add pnpm package manager support
• Fix vendored pnpm deployments calling pnpm install instead of pnpm rebuild #964 — Fix vendored pnpm deployments calling pnpm install instead of pnpm rebuild