libmoq: video.rs fails to compile on macOS (CVBuffer !Send across await)

[kixelated]

rs/libmoq/src/video.rs (added in #2145, NVDEC hardware decode) does not compile on macOS: moq_video::decode::Consumer holds a VecDeque<moq_video::decode::Frame> whose moq_video::frame::macos::Surface wraps a CoreVideo CFRetained<CVBuffer>, which is !Send. RawVideoConsumer::consume (video.rs:106) holds that consumer across an await inside tokio::spawn, so the future is !Send and fails to compile:

error: future cannot be sent between threads safely
  --> rs/libmoq/src/video.rs:106:3
  = help: within `objc2_core_video::...::CVBuffer`, the trait `Send` is not implemented for `*const UnsafeCell<()>`
  ...
  = note: required because it appears within `moq_video::decode::Consumer`

This is unrelated to the moq-net API review; it's a pre-existing gap because CI builds libmoq on Linux only, and the NVDEC decode path's macOS build was never exercised (see the "moq-nvenc vendored" / "NOT runtime-tested macOS" notes).

Options: give the decode task a spawn_local/single-thread path on macOS, wrap the CVBuffer surface in a Send newtype at the FFI boundary if the CoreVideo handle is actually thread-safe to move (it generally is; VideoToolbox already does unsafe impl Send), or gate moq_consume_video_raw off on macOS until decode is Send there. Add a macOS libmoq compile job to CI so this can't regress silently.

(Written by Claude Fable 5)

[coderabbitai]

🔗 Related PRs

#1071 - Uniffi async objects [closed]
#1155 - Add generic ordered::Consumer/Producer to moq-mux [closed]
#1163 - Use typed ordered::Consumer for video/audio in moq-ffi [closed]
#1782 - fix(ci): unbreak the self-hosted A1 runner (libmoq clippy + ffmpeg bindgen headers) [merged]
#1875 - fix: link macOS CoreServices for the bundled notify/FSEvents backend [merged]

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[kixelated]

Fixed on dev by #2162 (fix(moq-video): make decode Frame/Consumer Send on macOS), which makes moq_video::decode::{Frame, Consumer} Send on macOS. Verified: cargo check -p libmoq --all-targets now compiles cleanly on macOS. Closing as resolved.

(Written by Claude Fable 5)