Problem

detectPackageManager (and detectPackageManagerName) in utils/project.ts had two bugs that combined to make vinext deploy fail in Bun monorepos:

1. Wrong lockfile name. The function only checked for bun.lockb — the legacy binary format. Bun v1.0+ writes a text-based bun.lock file. Projects using Bun ≥ v1.0 were not detected as Bun workspaces.

2. No upward directory traversal. In a monorepo the lock file lives at the workspace root, not inside each app directory. When called from e.g. apps/web/, the function only checked that directory — missed the root — and fell through to npm install -D.

Both issues together produced this confusing error at the end of the npm fallback:

npm error Invalid Version:
Error: Command failed: npm install -D @cloudflare/vite-plugin@latest wrangler@latest @vitejs/plugin-rsc@latest
    at installDeps (dist/deploy.js:534:5)

Fix

• Add bun.lock check alongside the existing bun.lockb check.
• Walk up parent directories (stopping at the filesystem root) until a lock file is found, mirroring how npm/pnpm/yarn resolve workspace roots.
• Both changes applied to detectPackageManager (returns install command) and detectPackageManagerName (returns pm name).

The helper is refactored into two small functions: checkLockFiles (single-directory check) and findLockFile (the upward walk), keeping each unit testable in isolation.

Tests

7 new unit tests in tests/deploy.test.ts:

• pnpm detection via pnpm-lock.yaml
• yarn detection via yarn.lock
• bun detection via bun.lock (text, new)
• bun detection via bun.lockb (binary, legacy)
• npm fallback when no lock file found
• monorepo root traversal (apps/web/ → lock file at workspace root)
• closest-lock-wins precedence (inner pnpm-lock.yaml beats outer bun.lock)

✓ detects pnpm from pnpm-lock.yaml
✓ detects yarn from yarn.lock
✓ detects bun from bun.lock (text format, Bun v1.0+)
✓ detects bun from bun.lockb (legacy binary format)
✓ falls back to npm when no lock file is found
✓ walks up to parent directory to find lock file (monorepo root)
✓ prefers the closest lock file when both child and parent have one

pnpm run lint and pnpm run typecheck pass clean.

/bonk