# Issue #75 Compression Contracts Review

## Scope

- Issue: #75, "Define compression error, config, and stream contracts"
- Milestone: 0.4.0
- Branch: `issue-75-compression-contracts`
- Baseline: `origin/develop` at `431e892d0d476f66057b1ce5168a3bbb89e56de7`
- Review gate: Step 6-R local/native 7-Tier review
- Reviewed scope: `crates/compression`, root facade/docs, `README.md`, `README.ko.md`, `WIP.md`, `CHANGELOG.md`

## 7-Tier Result

| Tier | Agent role | Result | Evidence |
|---|---|---:|---|
| 1 Security | `security-reviewer` | PASS, P0=0 P1=0 | Verified 64 MiB default limit, lz4/snappy declared-size rejection before decode allocation, stream limit tests, and thread stress coverage. |
| 2 Ops/SRE reliability | `sre-reviewer` | PASS, P0=0 P1=0 | Re-review verified deterministic failing `Read`/`Write` tests, typed IO sources, direct reader limit source preservation, and default limit assertion. |
| 3 Structural/API | `architect-reviewer` | PASS, P0=0 P1=0 | Re-review verified `decompress_with_config` is defaulted for source compatibility, old-shape custom `Compressor` implementor test, no-default clippy, and typed `UnsupportedOperation` fallback. |
| 4 Rust code quality | `code-reviewer` | PASS, P0=0 P1=0 | Verified typed errors/source, Rustdoc, feature cfg, no production panic/todo, stream constructors, and boxed snappy writer enum sizing. |
| 5 Tests/types | `test-engineer` | PASS, P0=0 P1=0 | Verified no-default clippy, direct `decompression_reader` limit test, corrupted framed stream failures, one-shot/stream/limit-failure stress tests. |
| 6 Performance/stability | `performance-reviewer` | PASS, P0=0 P1=0 | Verified lz4/snappy preallocation protection, bounded stream copy behavior, large enum boxing, exact-limit tests, and stress evidence. |
| 7 Documentation/evidence | `library-user-reviewer` | PASS, P0=0 P1=0 | Re-review verified registry Rustdoc warns lz4/snappy one-shot block/raw versus framed stream payloads, trait summary, README parity, and rustdoc/doc tests. |
| Final verifier | `verifier` | PASS, P0=0 P1=0 | Verified issue requirements, typed config/error/stream contracts, feature matrix, stress tests, docs parity, and local validation evidence. |

## Blocker Convergence

| Iteration | P0 | P1 | Resolution |
|---|---:|---:|---|
| Initial Step 6-R | 0 | 6 | Fixed lz4/snappy preallocation limit checks, default 64 MiB limit, typed stream error taxonomy, stream constructors, and Rustdoc/docs parity. |
| Affected re-review | 0 | 3 | Fixed no-default clippy, IO failure tests, direct reader limit typed source, and public trait source compatibility. |
| Final affected re-review | 0 | 0 | Remaining Tier 3 and Tier 7 blockers re-reviewed clean. |

Final gate: PASS, `P0=0 P1=0`.

## Stress Test Evidence

The compression integration suite now includes bounded multi-thread stress tests:

- `compiled_algorithms_round_trip_stays_stable_across_threads`
- `compiled_algorithms_stream_round_trip_stays_stable_across_threads`
- `compiled_algorithms_limit_failures_stay_stable_across_threads`

Latest focused run:

- `cargo test -p bluetape-rs-compression --all-features --locked`: PASS, 24 integration tests + 3 doctests

## Validation Evidence

| Command | Result |
|---|---|
| `cargo fmt --all --check && git diff --check` | PASS |
| `cargo test -p bluetape-rs-compression --all-features --locked` | PASS, 24 integration tests + 3 doctests |
| `cargo test -p bluetape-rs-compression --no-default-features --locked` | PASS, 20 integration tests + 3 doctests |
| `for feature in gzip zlib deflate zstd lz4 snappy; do cargo test -p bluetape-rs-compression --no-default-features --features "$feature" --locked; done` | PASS |
| `cargo clippy -p bluetape-rs-compression --no-default-features --all-targets --locked -- -D warnings` | PASS |
| `cargo clippy -p bluetape-rs-compression --all-targets --all-features --locked -- -D warnings` | PASS |
| `rustup run 1.85.0 cargo check -p bluetape-rs-compression --all-targets --all-features --locked` | PASS |
| `cargo test --workspace --all-features --locked` | PASS |
| `cargo clippy --workspace --all-targets --all-features --locked -- -D warnings` | PASS |
| `RUSTDOCFLAGS="-D warnings" cargo doc --workspace --all-features --no-deps --locked` | PASS |
| `rustup run 1.85.0 cargo fmt --all --check && git diff --check && rustup run 1.85.0 cargo check --workspace --all-targets --all-features --locked && rustup run 1.85.0 cargo test -p bluetape-rs-compression --all-features --locked && rustup run 1.85.0 cargo clippy --workspace --all-targets --all-features --locked -- -D warnings && RUSTDOCFLAGS="-D warnings" rustup run 1.85.0 cargo doc -p bluetape-rs-compression --all-features --no-deps --locked` | PASS |

## Residual Notes

- GitHub CI and Step 7-R post-PR review are not part of this local Step 6-R artifact and must be run after PR creation.
- The default stream methods on custom `Compressor` implementors are source-compatibility fallbacks and buffer input; production streaming adapters override them.
