# V2 Rust Incremental Build Planning

`V2/ue/Tools/plan-v2-rust-incremental-build.py` minimizes Rust recompilation by
mapping changed files to their owning Cargo package and rebuilding only that
crate plus local reverse dependents. It reuses the crate graph scheduler from
`plan-v2-rust-crate-schedule.py`, so impacted crates still compile in
topological, critical-path-prioritized waves.

The planner treats Rust source files, `Cargo.toml`, `Cargo.lock`, and `build.rs`
as rebuild inputs. Documentation, `target`, and `node_modules` paths are
ignored. Toolchain or cross-linker changes such as `rust-toolchain.toml` and
`V2/ue/Build/Rust/cargo-cross-config.toml` force a full graph rebuild.

The release evidence is `$(ArchiveRoot)/Rust/incremental-build-plan.json`. Horde
gates require `rust-incremental-impact-plan-generated` and keep the normal
recompile surface at or below 35 percent through
`rust-incremental-recompile-surface`.