Stage 0 test report

Recorded 2026-11-03 after the commands below. CI has not run. Linux x86_64 is configured in .github/workflows/ci.yml and is untested here.

Environment

rustup on this machine is an x86_64 binary running under emulation. The toolchains it installed and the rustc processes used above are aarch64.

Commands

Default build, no F3_BUILD_NATIVE:

mix test
15 passed (3 doctests, 12 tests)
mix format --check-formatted
mix docs

mix format --check-formatted exited 0. mix docs wrote doc/index.html.

Optional NIF, then a return to the default build:

F3_BUILD_NATIVE=1 mix compile --force --warnings-as-errors
F3_BUILD_NATIVE=1 mix test test/f3/contract_test.exs
12 passed (3 doctests, 9 tests)

priv/native/f3_native.so is a Mach-O arm64 dylib. F3.Native.info/0 returned {:ok, {"f3_native", "0.0.1"}} under that test. The crate version is now 0.1.0. A later mix compile --force without the flag restored the default beam, and mix test passed again with available?/0 false.

Fixture generation:

scripts/fixtures/generate.sh

Eight files were written: small.f3, nullable.f3, wide.f3, multi_row_group.f3, compressed_zstd.f3, compressed_lz4.f3, dictionary.f3 (LocalDictionary), nested.f3 (struct and list<int32>). custom_wasm.f3 was skipped. fff-ude-example-fff failed to build for wasm32-wasip1 because clang could not find stdlib.h, string.h, stdio.h, and assert.h while compiling zstd-sys. The manifest records that reason. No Wasm fixture was invented.

mix run examples/tutorial_02.exs printed the tail of the committed small.f3 (4168 bytes, SHA-256 6f1ff9d7202c3f0d8f910a4ef154ba195cd225804d261ca752339cc8fc123a13). That output is copied into tutorial 2.

Not measured

No throughput, RSS, or scheduler numbers. Linux x86_64 and Linux arm64 were not executed. The GitHub Actions file is present and has not been run from this machine.

Implemented

The Mix library at the repository root opens a local path or an in-memory binary and closes that handle. lib/f3.ex refuses schema, metadata, read, stream, and inspect with :not_implemented. lib/f3/writer.ex refuses open, write, and close the same way. lib/f3/format.ex holds the pinned constants and compatible?/2. lib/f3/io/local.ex and lib/f3/io/memory.ex implement size, positioned read, and idempotent close. lib/f3/error.ex is the error struct. Schema, metadata, row group, and batch structs exist and are not filled from a file.

native/f3_native is a stable-Rust version probe. It is compiled only when F3_BUILD_NATIVE=1. It does not link fff-poc.

scripts/fixtures/generate.sh clones the pinned upstream commit, builds FileWriter from scripts/fixtures/generator/src/main.rs with that checkout's Cargo.lock, and writes test/fixtures/*.f3 plus test/fixtures/manifest.json.

Public API

F3.open/2 and F3.close/1 work. The other public calls do not read the format:

{:ok, file} = F3.open("test/fixtures/small.f3")
{:error, %F3.Error{category: :not_implemented}} = F3.schema(file)
:ok = F3.close(file)
{:error, %F3.Error{category: :closed}} = F3.schema(file)

F3.Format.compatible?(0, 1) is true. Any other pair is false. F3.Native.available?/0 is false unless the module was compiled with the native flag. There is no application callback.

Documentation

Tutorials 1 and 2 are technically reviewed. The hex dump in tutorial 2 matches the committed small.f3 (4168 bytes, SHA-256 6f1ff9d7202c3f0d8f910a4ef154ba195cd225804d261ca752339cc8fc123a13). examples/tutorial_01.exs and examples/tutorial_02.exs run under mix test. Tutorials 3–9 are backlog entries in docs/tutorials/README.md and have no article files. docs/tutorials/publication-plan.md does not schedule or post anything. Compatibility, architecture, the feature matrix, security notes, and ADR 0001 are in docs/.

Next stage

Stage 1 is a postscript decoder checked against these fixtures: bounds, magic, version, and truncation, with no FlatBuffers walk and no row reader. The footer checksum and the out-of-band column metadata stay unread until that decoder exists. Regenerating fixtures can change bytes because the upstream writer samples with thread_rng, so a new manifest has to replace the tutorial 2 dump from a new mix run examples/tutorial_02.exs.