Merge remote-tracking branch 'origin/main' into dh/recover-3324-rocm-dockerfile

The image did not build. bitsandbytes pins scikit-build-core unbounded in
build-system.requires, so the builder always resolves the newest release.
1.0.0 (2026-07-06) added a PEP 660 gate to the setuptools plugin backend that
bitsandbytes uses, rejecting editable installs unless pyproject sets
editable.mode = "inplace". The pin here is from March and predates upstream
adding that line, so pip install -e . dies in prepare_metadata_for_build_editable
with "setuptools editable installs require editable.mode = 'inplace'".
Verified by version bisection in the image: 0.11.6 and 0.12.2 install cleanly,
1.0.0, 1.0.1 and 1.0.3 all fail.

Install non-editable instead. Upstream's own install docs annotate the -e as
being for bitsandbytes development and say to leave it out otherwise, and an
editable checkout buys nothing in an image while tying the build to a
scikit-build-core knob that keeps moving. CMakeLists writes the library
straight into the package dir, so setuptools package-data ships exactly what
cmake built: the installed libbitsandbytes_rocm64.so is md5 identical to the
compiled one and its .hip_fatbin still holds a single gfx942 bundle.

The verification step could not fail. pip show passes on dist-info alone, so a
missing or unloadable HIP library left it green on precisely the broken image
it exists to catch. Load the artifacts instead. bitsandbytes cannot self-report
here: with no AMD GPU on the builder get_cuda_specs returns None, it loads
libbitsandbytes_cpu.so and hands back a healthy BNBNativeLibrary even after the
ROCm library is deleted, so the check globs for libbitsandbytes_rocm*.so beside
the installed package and ctypes.CDLL loads it. unsloth_zoo raises
NotImplementedError on import without a torch accelerator, so it and unsloth
are resolved with importlib.util.find_spec rather than executed.

Deleting the library now fails the check; the intact image passes.

The amdgpu-arch warning at configure time is benign and left alone. It comes
from hip-config-amd.cmake, pulled in by find_package(hipblas), and only governs
--offload-arch on the hip::device interface for CXX sources. bitsandbytes links
hip::host and compiles its kernels as HIP, taking the arch from
CMAKE_HIP_ARCHITECTURES, which BNB_ROCM_ARCH sets before enable_language(HIP).
The built library contains gfx942 and no gfx906.

docker/Dockerfile.rocm

@@ -0,0 +1,69 @@
+ARG BASE_DOCKER=rocm/vllm-dev:nightly_main_20250914
+FROM $BASE_DOCKER
+
+WORKDIR /unsloth-workspace
+
+# Single RUN so the apt index can't go stale; cleanup keeps the layer small.
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends zip unzip wget build-essential cmake \
+    && rm -rf /var/lib/apt/lists/*
+
+ARG COMPUTE_BACKEND="hip"
+ARG BNB_ROCM_ARCHS="gfx942"
+# bnb PR #1887 floor (0.50.0.dev0); earlier builds NaN at 4-bit GEMV decode on AMD.
+ARG BNB_COMMIT="713a3b83e405d32449e1cb392e5e25985ab927c6"
+ARG BNB_REPO="https://github.com/bitsandbytes-foundation/bitsandbytes.git"
+
+# Plain install, not `-e`: upstream reserves editable for bnb development, and
+# scikit-build-core 1.0.0 rejects it unless pyproject opts into
+# editable.mode = "inplace", which this pin predates. cmake already dropped the
+# .so into the package dir, so setuptools package-data ships it as built.
+RUN mkdir bitsandbytes \
+    && cd bitsandbytes \
+    && git init \
+    && git remote add origin ${BNB_REPO} \
+    && git fetch --depth 1 origin ${BNB_COMMIT} \
+    && git checkout FETCH_HEAD \
+    && rm -rf .git \
+    && cmake -S . -B build \
+         -DCOMPUTE_BACKEND=${COMPUTE_BACKEND} \
+         -DBNB_ROCM_ARCH="${BNB_ROCM_ARCHS}" \
+    && cmake --build build -j"$(nproc)" \
+    && pip install . \
+    && rm -rf build
+
+ARG UNSLOTH_REPO="https://github.com/unslothai/unsloth.git"
+ARG UNSLOTH_BRANCH="main"
+
+
+# huggingfacenotorch skips torch/torchvision so the base image's ROCm torch survives; bare `-e .` can't train.
+RUN git clone --branch ${UNSLOTH_BRANCH} --depth 1 ${UNSLOTH_REPO} unsloth \
+    && cd unsloth \
+    && rm -rf .git \
+    && pip install -e '.[huggingfacenotorch]'
+
+
+ARG UNSLOTH_ZOO_REPO="https://github.com/unslothai/unsloth-zoo.git"
+ARG UNSLOTH_ZOO_BRANCH="main"
+
+RUN git clone --branch ${UNSLOTH_ZOO_BRANCH} --depth 1 ${UNSLOTH_ZOO_REPO} unsloth-zoo \
+    && cd unsloth-zoo \
+    && rm -rf .git \
+    && pip install -e .
+
+
+# pip show reads dist-info only, so it stayed green on an image whose freshly
+# compiled HIP library was missing. bitsandbytes is no help either: with no AMD
+# GPU on the builder it falls back to libbitsandbytes_cpu.so and reports
+# success, so load the ROCm library explicitly. unsloth_zoo refuses to import
+# without a torch accelerator, so only resolve it and unsloth.
+# Still uncaught: a wrong-arch build loads fine here and only fails once a
+# 4-bit GEMV runs on real AMD silicon.
+RUN python3 -c "import ctypes, importlib.util, pathlib; \
+    import bitsandbytes; \
+    pkg = pathlib.Path(bitsandbytes.__file__).parent; \
+    libs = sorted(pkg.glob('libbitsandbytes*.so')); \
+    assert any('_rocm' in so.name for so in libs), f'no libbitsandbytes_rocm*.so in {pkg}'; \
+    [ctypes.CDLL(str(so)) for so in libs]; \
+    missing = [m for m in ('unsloth', 'unsloth_zoo') if importlib.util.find_spec(m) is None]; \
+    assert not missing, f'not importable: {missing}'"