release: 0.5.0

[rubas]

Release 0.5.0 of whisper_cpp.

Why this release

• CPU baseline for the precompiled NIFs ([P2] Pin a CPU instruction baseline for the precompiled release artefacts #44). The published aarch64 Linux artefacts of 0.2.0 to 0.4.1 carry SVE and i8mm code and can die with SIGILL on Graviton2, Ampere Altra, Raspberry Pi 5, and Jetson Orin. Only a new release fixes that. x86_64 Linux now has an explicit AVX2, FMA, F16C, and BMI2 baseline. The cuda artefacts carry kernels for the ggml release GPU list, not only sm_52 PTX.
• whisper.cpp 1.8.6 -> 1.9.4 ([P2] Move the vendored whisper.cpp submodule from v1.8.6 to v1.9.4 #47). Memory-safety fixes: a heap out-of-bounds read for 1 to 200 samples, a stack buffer overflow on a malformed model file, and a C++ exception that could escape into the NIF during a model load.
• Caller-visible fixes. Inputs that raised now return :invalid_request ([P3] Pcm.slice raises instead of returning invalid_request for very large times #53, [P3] Three accepted inputs raise at the NIF boundary instead of returning invalid_request #54, [P3] The short-slice path does not apply the full native request contract #55). Transcription.language is always the ISO code ([P3] An empty result reports the requested language name instead of the ISO code #52). Native error messages lose the kind= tag ([P3] Native error messages still carry the internal kind= routing tag #48). Word timestamps work for scripts without spaces ([P3] word_timestamps returns one word per segment for scripts without spaces #51). 1 to 40 samples with auto-detect return an empty result ([P3] Audio shorter than 41 samples returns an error when the language is auto-detected #66). Build variables recompile the wrapper ([P2] Backend build tasks do not recompile the NIF wrapper when the selection changes #46), and an unpublished WHISPER_CPP_VARIANT fails the compile ([P3] An unavailable variant silently falls back to the default artefact #49).
• Source builds need Rust 1.98 ([P3] CI no longer checks the declared MSRV 1.91 #60).

Several changes are caller-visible, so this is a minor bump. CHANGELOG.md names the action for each one.

Included PRs

• ci: bump Elixir to 1.20.3 and OTP to 29.0.5 #38 ci: bump Elixir to 1.20.3 and OTP to 29.0.5
• docs: correct the changelog #39 docs: correct the changelog
• chore: speed up native crate builds #40 chore: speed up native crate builds
• ci: zizmor 1.30.1 and the same-repository action ref #41 ci: zizmor 1.30.1 and the same-repository action ref
• Remove CLAUDE.md #42 Remove CLAUDE.md
• chore: update deps and CI toolchains #59 chore: update deps and CI toolchains
• chore: move the vendored whisper.cpp to v1.9.4 #62 chore: move the vendored whisper.cpp to v1.9.4 (closes [P2] Move the vendored whisper.cpp submodule from v1.8.6 to v1.9.4 #47)
• ci: build releases from the tag, pin a CPU baseline, add job timeouts #63 ci: build releases from the tag, pin a CPU baseline, add job timeouts (closes [P2] Build manual releases from the requested tag, not the dispatch ref #43, [P2] Pin a CPU instruction baseline for the precompiled release artefacts #44, [P3] Set a job timeout on the CI and security workflows #56)
• fix: return invalid_request instead of raising, and honour build selection #64 fix: return invalid_request instead of raising, and honour build selection (closes [P2] Backend build tasks do not recompile the NIF wrapper when the selection changes #46, [P3] An unavailable variant silently falls back to the default artefact #49, [P3] Pcm.slice raises instead of returning invalid_request for very large times #53, [P3] Three accepted inputs raise at the NIF boundary instead of returning invalid_request #54, [P3] The short-slice path does not apply the full native request contract #55)
• fix: native error messages, language code, CJK words, coreml cpu, abort test #65 fix: native error messages, language code, CJK words, coreml cpu, abort test (closes [P2] The abort-callback regression test no longer reaches the callback #45, [P3] Native error messages still carry the internal kind= routing tag #48, [P3] A CoreML source build ignores device: :cpu #50, [P3] word_timestamps returns one word per segment for scripts without spaces #51, [P3] An empty result reports the requested language name instead of the ISO code #52)
• chore: declare MSRV 1.98 and pin Task with a checksum #67 chore: declare MSRV 1.98 and pin Task with a checksum (closes [P3] CI no longer checks the declared MSRV 1.91 #60, [P3] Pin the Task version and checksum in the setup action #61)
• fix: return an empty transcription for audio too short for language detection #68 fix: return an empty transcription for audio too short for language detection (closes [P3] Audio shorter than 41 samples returns an error when the language is auto-detected #66)

Issue #26 stays open: whisper-rs upstream has no release with the trampoline fix.

Changes in this PR

• mix.exs: @version 0.4.1 -> 0.5.0.
• CHANGELOG.md: the 0.5.0 entry. It replaces the [Unreleased] CI entry, which named Elixir 1.20.3 and OTP 29.0.5; CI now uses 1.20.4 and 29.1.1.
• README.md: install snippet ~> 0.5.0, and the CPU baseline note says "from 0.5.0 on".
• The native crate keeps its own version (0.1.0).

Risks for the release run

• Only the CPU variant was built at whisper.cpp 1.9.4 (chore: move the vendored whisper.cpp to v1.9.4 #62). The CUDA, HIP, and Metal variants compile for the first time in the release matrix.
• The aarch64, darwin, and CUDA builds with GGML_NATIVE=OFF (ci: build releases from the tag, pin a CPU baseline, add job timeouts #63) also run for the first time. The CUDA jobs take longer and the tarballs grow.
• fix: return invalid_request instead of raising, and honour build selection #64 replaced nif_known_language/1 with nif_resolve_language/2, so 0.5.0 needs new artefacts on every target. A missing tarball fails the install on that target.

After the merge, follow the AGENTS.md Release steps: wait for release.yml, regenerate checksum-Elixir.WhisperCpp.Native.exs, push it, then mix hex.publish.

Dependencies

mix hex.outdated: every Hex dependency is up to date. cargo update --dry-run: 0 packages to update.

Checks

• WHISPER_CPP_BUILD=1 task check: green. Format, compile with warnings as errors, credo --strict (no issues), ExUnit 62 passed and 22 excluded, cargo tests 33 passed, zizmor no findings.
• WHISPER_CPP_BUILD=1 task test:integration (ggml-tiny.en and ggml-tiny): 84 passed.
• No dprint.json in this repository, so no dprint fmt.

[rubas]

Review findings, checked against the tree. Fixes are in 4183374.

Opus

1. Fixed (4183374). The [P3] An empty result reports the requested language name instead of the ISO code #52 item now states the fix: return invalid_request instead of raising, and honour build selection #64 change on transcribe_slice/4 windows under 0.3 s. v0.4.1 used language || "" with the raw option, so nil gave "" and "auto" gave "auto". Now Native.resolve_language/2 gives "en" on an English-only model and "" on a multilingual model.
2. Fixed (4183374). v0.4.1 passed a non-UTF-8 path through String.trim/1 (it does not raise on invalid UTF-8), and Rustler then failed to decode path: String and raised ArgumentError. The Fixed list now names this input. The Changed entry now states the new message for an empty or blank path.
3. The date stays 2026-09-23. The merge happens today.

Astra

1. Fixed (4183374). The pinned whisper-rs-sys build defines WHISPER_COREML_ALLOW_FALLBACK=1 (sys/build.rs line 199 at rev 9a4232f). The entry now uses the README wording: the build uses the Core ML encoder whenever the model's -encoder.mlmodelc loads, and a caller cannot turn it off per model.
2. Declined. The changelog records changes that reach a caller or the published artefacts. ci: zizmor 1.30.1 and the same-repository action ref #41 changes only the zizmor version and an action reference in CI. Remove CLAUDE.md #42 removes a repository instruction file. Neither changes the package, the artefacts, or the release process. The PR body lists every included PR, ci: zizmor 1.30.1 and the same-repository action ref #41 and Remove CLAUDE.md #42 too.

Gate: WHISPER_CPP_BUILD=1 task check is green (format, compile with warnings as errors, credo strict, ExUnit 62 passed and 22 excluded, cargo tests 33 passed, zizmor no findings).