native modules: build rust workspace crates through the repo flake

dimos/mapping/ray_tracing/module.py

@@ -35,7 +35,11 @@ class RayTracingVoxelMapConfig(NativeModuleConfig):
     cwd: str | None = "rust"
     # The crate is a workspace member, so cargo builds into the repo-root target dir.
     executable: str = str(DIMOS_PROJECT_ROOT / "target" / "release" / "voxel_ray_tracing")
-    build_command: str | None = "cargo build --release"
+    # The repo flake supplies cargo: rustup's PATH entry is absent in non-interactive
+    # shells (ssh commands, systemd units). Relative to cwd rather than
+    # DIMOS_PROJECT_ROOT so it stays a literal the CI inputs hash can read, and because
+    # nix resolves it against the real cwd, sidestepping symlinked components (macOS /tmp).
+    build_command: str | None = "nix develop path:../../../.. -c cargo build --release"
     stdin_config: bool = True
 
     voxel_size: float = 0.1

dimos/navigation/nav_3d/mls_planner/mls_planner_native.py

@@ -31,7 +31,11 @@ class MLSPlannerNativeConfig(NativeModuleConfig):
     cwd: str | None = "rust"
     # The crate is a workspace member, so cargo builds into the repo-root target dir.
     executable: str = str(DIMOS_PROJECT_ROOT / "target" / "release" / "mls_planner")
-    build_command: str | None = "cargo build --release"
+    # The repo flake supplies cargo: rustup's PATH entry is absent in non-interactive
+    # shells (ssh commands, systemd units). Relative to cwd rather than
+    # DIMOS_PROJECT_ROOT so it stays a literal the CI inputs hash can read, and because
+    # nix resolves it against the real cwd, sidestepping symlinked components (macOS /tmp).
+    build_command: str | None = "nix develop path:../../../../.. -c cargo build --release"
     stdin_config: bool = True
 
     world_frame: str = "odom"

flake.nix

@@ -80,6 +80,10 @@
           { vals.pkg=pkgs.uv;                             flags={}; }
           { vals.pkg=pkgs.pre-commit;                   flags={}; }
 
+          ### Rust (native module auto-builds run `nix develop path:<repo> -c cargo`)
+          { vals.pkg=pkgs.cargo;                        flags={}; }
+          { vals.pkg=pkgs.rustc;                        flags={}; }
+
           ### Runtime deps
           { vals.pkg=pkgs.portaudio;                 flags={ldLibraryGroup=true; packageConfGroup=true;}; }
           { vals.pkg=pkgs.ffmpeg_6;                  flags={}; }