# Slice And List Boundary Helpers Review

## Scope

- Issue: #32
- Baseline: `origin/develop` at `bea771f`
- Reviewed diff: `crates/collections/src/slice.rs`, README, and research update

## Evidence

- `bluetape4k-core` source review: `safeSubList`, `padTo`, prepend/append, and swap helpers from `CollectionSupport.kt`
- Rust std overlap review: `Vec::swap`, `Vec::extend`, `Vec::insert`, `Vec::resize`, slice `chunks`, and slice `windows` deliberately not wrapped
- Accepted API rationale: `clamped_subslice` handles signed external bounds without allocation; `pad_to` uses `Cow<[T]>` to avoid allocation when no padding is needed
- `git diff --check`: PASS
- `cargo fmt --all --check`: PASS
- `cargo test -p bluetape-rs-collections`: PASS, 22 unit tests and 12 doctests
- `cargo test --workspace --all-features`: PASS
- `cargo clippy --workspace --all-targets --all-features -- -D warnings`: PASS
- `RUSTDOCFLAGS='-D warnings' cargo doc --workspace --no-deps`: PASS

## Findings

- P0: none
- P1: none
- P2: none
- P3: none

## 7-Tier Review

| Tier | Result | Evidence |
| --- | --- | --- |
| API contract | PASS | Rust-native borrowed slice and `Cow` APIs, no mutable Vec wrapper helpers |
| Correctness | PASS | clamped negative, oversized, reversed, and empty bounds covered |
| Allocation behavior | PASS | `pad_to` returns borrowed no-op result and owned padded result |
| Standard-library overlap | PASS | direct wrappers around `Vec` and slice built-ins excluded |
| Docs | PASS | Rustdoc examples pass doctests |
| Scope control | PASS | pagination remains split to #33 |
| Validation | PASS | fmt, tests, clippy, rustdoc warning gate |

## Gate

P0=0 P1=0

Verdict: PASS.
