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CLI lives in the monorepo (Phase 218)

The nros CLI lives in-tree at packages/cli/ as a sub-workspace — own Cargo.toml, own Cargo.lock, own member crates (nros-cli, nros-cli-core, nros-build, cargo-nano-ros, rosidl-*, colcon-cargo-ros2, nros-msg-to-idl). It is built per checkout via just setup-cli → packages/cli/target/release/nros, then put on PATH by the activate file. See also:

Why sub-workspace, not root member

The runtime workspace’s no_std feature-unification view (Phase 214.F.3) is the project’s most fragile invariant — a single workspace member adding a std-activating dep without target-gating turns the embedded build red on a path the test matrix doesn’t always exercise. The CLI’s deps (clap, askama, syn, ureq, …) are aggressively std-only; making them workspace siblings of the runtime crates would either (a) require target-gating every single one or (b) effectively disable the F.3 guard.

The sub-workspace shape keeps the two surfaces categorically separate. The pattern mirrors packages/testing/nros-{tests,bench,smoke}/, which carved out the same way for the same reason.

Why per-checkout, not ~/.nros/bin

Confirmed during the Phase 218 UX walkthrough: contributors with multiple nano-ros worktrees (phase branches, ASI integration trees, downstream forks) need each tree to point at its own CLI. A global install would silently version-skew across trees the moment the user cds — and because the CLI’s codegen format is structurally bound to the nros-core / nros-c / nros-cpp crates in the same checkout, a global CLI is a known footgun.

The per-checkout shape makes the activate file the single switch — no which nros surprise across cwd boundaries. One checkout = one CLI version = one runtime ABI, by construction; no version-pin matrix to police.

Resolution chain

scripts/build/cargo.sh::nros_cli_bin resolves the active binary:

  1. $NROS_CLI (explicit override)
  2. nros on $PATH (activate file puts the repo-local one here)
  3. packages/cli/target/release/nros (per-checkout)
  4. ${NROS_HOME:-~/.nros}/bin/nros (transitional, removed once every active branch lands on 218)
  5. error

The Phase 218.E ABI guard checks the in-tree CLI build matches the runtime crates’ codegen ABI hash; opt out via NROS_SKIP_VERSION_CHECK=1 when intentionally bisecting a CLI mismatch.

See also