# Vendored Lance v2.1 protobuf definitions
This directory pins the **Lance v2.1 format spec** that `genegraph-storage`'s
in-house implementation (#75, milestone M1+) targets.
## Provenance
- Source: [`lancedb/lance`](https://github.com/lancedb/lance) as shipped in
the `lance` crate **v11.0.0** (`protos/` directory, crates.io package).
- License: **Apache-2.0** — each file carries
`SPDX-License-Identifier: Apache-2.0` /
`SPDX-FileCopyrightText: Copyright The Lance Authors` headers, preserved
unmodified. See the root `NOTICE` file.
- Pinned: 2026-09-01, from the lance 11.0.0 crates.io release
(`file.proto`, `file2.proto`, `table.proto`, `encodings_v2_0.proto`,
`encodings_v2_1.proto`).
## Encoding policy (per #75, "never guess")
Our artifact schemas only require the **Flat** encoding with no compression
plus validity handling (none / all-set / bitmap). Files written by the
official crate that use any other encoding (bitpacking, FSST, dictionary,
full-zip, blob, general, ...) are **rejected with a typed error**
(`StorageError::UnsupportedFormat`), never guessed at.
## Interop conformance
The golden fixtures under `tests/fixtures/lancefmt/` were generated by the
official crate and are exercised by the in-house reader's test suite
(`tests::test_lancefmt_impl`), keeping the "official writer -> our reader"
interop bar green without a runtime or dev dependency on `lance`.
## Regeneration
These files are vendored verbatim and must not be hand-edited. To update the
pin, copy the `protos/` directory from the target `lance` crate release,
update the pinned version above and in the root `NOTICE`, and re-run the
conformance suite (`cargo test --release lancefmt`).