[TomCC7]

Linear project: Message Encoding Refactor

RealSense now publishes generated Image, CameraInfo, PointCloud2, Imu and project-owned ImuInfo values with CDR. The handwritten ImuInfo fingerprint/encoder is removed. Python port types and Rust registry names agree, including dimos_msgs/msg/ImuInfo.

The native TF SDK adds optional #[tf(decode = ..., encode = ...)] hooks. Existing bare #[tf], lookup and publish operations retain their behavior. RealSense selects canonical TFMessage CDR through these hooks; the generic SDK does not acquire a dependency on the built-in message catalog. Codec errors propagate, and one TF topic rejects mixed codec pairs.

The self-contained RealSense flake pins SDK/configuration source 62b899b2d3b0d315988df7db25664264391fb4ea, archive SHA256 8d920aba91b51ba63f18e4cd88cdfff95ff4f3aa2dfbb34f2ef209a59182c75c. It generates the same owner used by ordinary package builds. V4L2/RealSense crate hash keys now match the unchanged locked LCM transport source revision; no forked LCM code was changed.

An installed SDK test also exposed a packaging defect: the SDK Cargo manifest declared an example whose source was omitted from the wheel. The wheel/sdist now carry that existing source unchanged. The fix is also published in its owning SDK layer #4649 at 6065e638b117f3fac565afde4e27aeeed4d35a4d. The SDK example is shipped byte-identically. No benchmark was executed, investigated or tuned. The existing ignored RealSense benchmark only received the field/codec substitutions required for the generated value types to compile.

Dependent draft after #4656. ZED, downstream consumers, default-transport cutover and final cleanup remain later work. No camera worker main, device enumeration/capture, robot, installer, firmware tool or driver operation was run. No registry publication.

Validation

Published head: a4313e544d0eb064a455bbbe5b1e5f503b788f63. Functional/package acceptance ran on 9deac468ad978eaeba80bb29b384a19c6ab4ae10; the final two commits only align native hash metadata.

• 148 native SDK tests and 22 macro tests passed. Clippy passed with warnings denied; default feature compilation passed.
• Official librealsense 2.56.5 source was built in the task workspace. Its library linked six passing RealSense regression tests. The same six passed in the exact pinned SDK/generated-owner/local-worker source assembly. No install target or host ldconfig was run.
• Five actual Rust CDR fixtures decoded as installed Python owners and re-encoded identically. Checks include TF, calibration, RGB image, point-cloud positions/colors/source time, and IMU noise metadata. Tests use real SDK intrinsics and synthetic frame data.
• 48 Python camera/viewer checks passed from source and from the installed wheel. Strict typing passed eight camera/viewer sources.
• The SDK export fix passed eight build checks and strict build-helper typing. A fresh sdist rebuilt a wheel; artifact inventory passed. Installed SDK + installed generated Rust owner then compiled and passed the six RealSense tests outside checkout imports. pip check passed. The wheel SHA256 is 48e8a41295eb8d9caf3275c525f3d9f45a67f778f1e4d6d533e187b10a3ae524.
• Existing native path-isolation and locked-source hash checks pass at the published head. Available hooks passed. Nix lint/derivation execution remains unverified because this host has no Nix executable. ARM and physical capture remain unverified. CI was not polled; no all-green claim.

Try it without a camera

The embedded walkthrough lists ports, artifacts and prerequisites. On a Nix development host:

cd dimos/hardware/sensors/camera/realsense/rust
nix build path:.#tests

For a repository developer with the checkout installed, Rust/C toolchains and librealsense available through pkg-config:

cargo test --manifest-path dimos/hardware/sensors/camera/realsense/rust/Cargo.toml \
  --locked --bin realsense_native --jobs 2 -- tests:: --skip bench::

The Nix command was not run locally. The Cargo regressions were run with the isolated official SDK build tree. They check encoding, normalized timestamps in both byte orders, calibration/projection, frame/color alignment and IMU pairing; they do not start capture. The existing floating-point graph-time API is retained; raw CDR uses generated Time fields.

File change summary

Three-dot diff from merge-base 5385ae1df08b5ae8091cdc2f4aee9002cf73acd6: 17 files, 603 additions and 155 deletions, excluding binary lockfile line counts. Parent #4656 also has later autofix commits; final stack alignment remains scheduled after the remaining slices.

Category	Files	Added	Deleted
Native TF SDK, macro and regressions	3	243	38
Python/native camera and regression tests	3	261	87
Native manifest and isolated Nix assembly	2	39	17
Wheel/sdist SDK export completeness	4	7	1
Locked-source hash metadata	2	4	8
Documentation and CI	2	49	4
Cargo dependency lock	1	binary	binary

No generated message classes or upstream .msg snapshots are checked in.