pika-orch-incus-cleanup-17

The old ensure_remote_linux_vm_directories built a shell command with a concat! macro that assembled three clauses:

1. mkdir -p for the six core directories.
2. A conditional if [ ! -e ... ] && [ ! -L ... ]; then mkdir -p ...; fi for workspace-deps.
3. The same conditional for workspace-build.

The conditionals existed because a prior step could install symlinks at those paths (pointing to local staged payload directories on localhost). Creating the directory over an existing symlink would have been an error.

With symlinks removed from the workflow, these guards are unnecessary. The format string collapses to a single mkdir -p with eight positional arguments, and the duplicated shell_single_quote calls for the conditional branches are deleted. The two staged output paths (remote_workspace_deps_dir, remote_workspace_build_dir) are now created unconditionally alongside every other directory.

Two major deletions happen here:

1. remote_symlink — a 15-line helper that ran mkdir -p <parent>; ln -sfn <target> <link> over SSH. It was only called from the localhost staged-payload block that is also being removed.

2. The localhost symlink-installation block inside prepare_remote_linux_vm_runtime — this block checked ssh_host_is_local, resolved each local staged payload path with fs::canonicalize, and called remote_symlink to create symlinks at the remote workspace deps/build directories. All of this logic is replaced by passing ctx: &HostContext through to incus::prepare_runtime, letting the Incus module handle source resolution at device-configuration time.

The prepare_remote_linux_vm_runtime function body reduces to a single match expression that forwards ctx into the backend.

Three function signatures gain a ctx: &HostContext parameter:

• prepare_runtime — the public entry point from executor.rs.
• ensure_remote_incus_runtime — creates the Incus instance and configures devices.
• configure_remote_incus_devices — the function that actually adds disk devices to the container.

This threading is mechanical: each caller passes ctx through unchanged. The important consumer is configure_remote_incus_devices, which will use ctx.staged_linux_rust_workspace_deps_dir and ctx.staged_linux_rust_workspace_build_dir to resolve the correct source path for each device mount.

staged_payload_source_root encapsulates the localhost detection that was previously done in prepare_remote_linux_vm_runtime:

• Localhost path: When ssh_host_is_local(remote_host) is true, the function requires a local_mount_path (from HostContext) and canonicalizes it with fs::canonicalize. If the local path is None, it returns an explicit error instead of silently skipping (a strictness improvement over the old code which used if let Some(...)).
• Remote path: For non-localhost hosts, it returns remote_output_root as-is, since the path is already on the remote machine's filesystem.

This function is private to the Incus module, keeping the resolution logic co-located with the device configuration that consumes it.

Inside configure_remote_incus_devices, the staged payload mount block now:

1. Calls staged_payload_source_root for workspace-deps, passing ctx.staged_linux_rust_workspace_deps_dir as the optional local path.
2. Passes the resolved workspace_deps_root to add_declared_payload_mounts.
3. Repeats the same pattern for workspace-build.

Previously, add_declared_payload_mounts received &remote.shared.remote_workspace_deps_dir directly, which on localhost was expected to be a symlink pointing to the real local directory. Now the real path is computed up front and handed to the mount helper, eliminating the symlink dependency entirely.

Testing changes cover three areas:

1. resolve_staged_payload_source_root_for_test (incus.rs) — a #[cfg(test)] pub(super) wrapper that lets tests in the parent module call the private staged_payload_source_root without exposing it in production builds.

2. Renamed test — ensure_remote_linux_vm_directories_skips_existing_staged_output_symlinks becomes ensure_remote_linux_vm_directories_create_declared_staged_output_dirs. The assertions are updated: the test now verifies that both staged paths appear in the mkdir -p argument list and that no if [ ! -e conditional remains in the command string.

3. Two new tests:

   • remote_linux_incus_uses_local_staged_payload_mount_for_localhost — creates a temporary directory, calls resolve_staged_payload_source_root_for_test with remote_host = "localhost", and asserts the result equals the canonicalized local path.
   • remote_linux_incus_preserves_remote_staged_payload_root_for_non_localhost — calls with remote_host = "pika-build" and local_mount_path = None, asserts the remote path is returned unchanged.

The use chrono::Utc import is added to the test module to support unique temp directory naming via timestamp_nanos_opt.