Move build system to meson-python

.flake8

@@ -28,7 +28,9 @@ per-file-ignores =
     mkl_umath/ufunc_docstrings_numpy1.py: E501
     mkl_umath/ufunc_docstrings_numpy2.py: E501
 
-exclude = _vendored/conv_template.py
+exclude =
+    _vendored/conv_template.py
+    _vendored/process_src_template.py
 
 filename = *.py, *.pyx, *.pxi, *.pxd
 max_line_length = 80

.github/AGENTS.md

@@ -1,25 +1,16 @@
 # AGENTS.md — .github/
 
-CI/CD workflows, automation, security scanning, and package distribution.
+CI/CD workflows and repo automation.
 
-## Workflows
-- **conda-package.yml** — main build/test pipeline (Linux/Windows, Python 3.10-3.14)
-- **build_pip.yaml** — PyPI wheel builds for Intel channel
-- **build-with-clang.yml** — Clang compatibility validation
-- **openssf-scorecard.yml** — security posture scanning
+## Workflows (source of truth)
+- `conda-package.yml` — Intel channel conda build/test pipeline
+- `conda-package-cf.yml` — conda-forge-oriented build/test pipeline
+- `build-with-clang.yml` — Intel clang compatibility checks
+- `build-with-standard-clang.yml` — standard clang compatibility checks
+- `build_pip.yml` — pip build pipeline with pre-release NumPy
+- `pre-commit.yml` — lint/format checks
+- `openssf-scorecard.yml` — security scanning
 
-## CI/CD policy
-- Keep build matrix (Python versions, platforms) in workflow files only
-- Required checks: conda build + test on all supported Python versions
-- Artifact naming: `$PACKAGE_NAME $OS Python $VERSION`
-- Conda channel: `https://software.repos.intel.com/python/conda`
-
-## Security
-- OpenSSF Scorecard runs automatically
-- CODEOWNERS enforces review policy
-- Dependabot monitors dependencies (`.github/dependabot.yml`)
-
-## Notes
-- Workflow/job renames are breaking for downstream tooling
-- Cache key includes `meta.yaml` hash for conda packages
-- Artifacts uploaded per-Python-version for parallel testing
+## Policy
+- Treat workflow YAML as canonical for platform/Python matrices.
+- Avoid doc claims about CI coverage unless present in workflow config.

.github/copilot-instructions.md

@@ -32,10 +32,10 @@ Higher-precedence rules override lower-precedence context.
 - Never include secrets or credentials in code/docs.
 
 ## Source-of-truth files
-- Build: `CMakeLists.txt`, `pyproject.toml`, `setup.py`
-- Dependencies/packaging: `conda-recipe*/meta.yaml`
-- CI: `.github/workflows/*.{yml,yaml}`
-- API: `mkl_umath/__init__.py`, `mkl_umath/src/_patch.pyx`
+- Build/config: `pyproject.toml`, `meson.build`
+- Dependencies/packaging: `pyproject.toml`, `conda-recipe*/meta.yaml`
+- CI: `.github/workflows/*.yml`
+- API: `mkl_umath/__init__.py`, `mkl_umath/src/_patch_numpy.pyx`
 - Core implementation: `mkl_umath/src/*.{c,c.src,pyx}`
 - Tests: `mkl_umath/tests/`
 

.github/workflows/build-with-clang.yml

@@ -3,18 +3,18 @@ name: Build project with IntelLLVM clang compiler
 on:
   pull_request:
   push:
-    branches: [master]
+    branches: [main]
 
 permissions: read-all
 
 jobs:
-  build-with-clang:
+  build-with-intel-clang:
     runs-on: ubuntu-latest
 
     strategy:
       matrix:
         python: ["3.10", "3.11", "3.12", "3.13", "3.14"]
-        numpy_version: ["numpy'>=2'"]
+        numpy_version: ["'numpy>=2'"]
 
     env:
       ONEAPI_ROOT: /opt/intel/oneapi
@@ -55,7 +55,7 @@ jobs:
 
       - name: Install mkl_umath dependencies
         run: |
-          pip install scikit-build cmake ninja cython setuptools">=77"
+          pip install meson-python ninja cython cmake
           pip install ${{ matrix.numpy_version }}
 
       - name: List oneAPI folder content
@@ -66,14 +66,10 @@ jobs:
           source ${{ env.ONEAPI_ROOT }}/setvars.sh
           echo "$CMPLR_ROOT"
           export CC="$CMPLR_ROOT/bin/icx"
-          export CFLAGS="${CFLAGS} -fno-fast-math -O2"
-          pip install . --no-build-isolation --no-deps --verbose
+          pip install -e . --no-build-isolation --no-deps --verbose
 
       - name: Run mkl_umath tests
         run: |
           source ${{ env.ONEAPI_ROOT }}/setvars.sh
           pip install pytest
-          # mkl_umath cannot be installed in editable mode, we need
-          # to change directory before importing it and running tests
-          cd ..
           python -m pytest -sv --pyargs mkl_umath

.github/workflows/build-with-standard-clang.yml

@@ -0,0 +1,60 @@
+name: Build project with standard clang compiler
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+
+permissions: read-all
+
+jobs:
+  build-with-standard-clang:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        python: ["3.10", "3.11", "3.12", "3.13", "3.14"]
+        numpy_version: ["'numpy>=2'"]
+
+    env:
+      COMPILER_ROOT: /usr/bin
+
+    defaults:
+      run:
+        shell: bash -el {0}
+
+    steps:
+      - name: Cancel Previous Runs
+        uses: styfle/cancel-workflow-action@3155a141048f8f89c06b4cdae32e7853e97536bc # 0.13.0
+        with:
+          access_token: ${{ github.token }}
+
+      - name: Install Dependencies
+        run: |
+          sudo apt-get update && sudo apt-get install -y clang
+
+      - name: Setup Python
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
+        with:
+          python-version: ${{ matrix.python }}
+          architecture: x64
+
+      - name: Checkout repo
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          fetch-depth: 0
+
+      - name: Install mkl_umath dependencies
+        run: |
+          pip install meson-python ninja cmake cython mkl-devel
+          pip install ${{ matrix.numpy_version }}
+
+      - name: Build mkl_umath
+        run: |
+          export CC=${{ env.COMPILER_ROOT }}/clang
+          pip install -e . --no-build-isolation --no-deps --verbose
+
+      - name: Run mkl_umath tests
+        run: |
+          pip install pytest
+          python -m pytest -sv --pyargs mkl_umath

.github/workflows/build_pip.yaml → .github/workflows/build_pip.yml

@@ -3,7 +3,7 @@ name: Build using pip and pre-release NumPy
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 
 permissions: read-all
@@ -21,11 +21,6 @@ jobs:
         use_pre: ["", "--pre"]
 
     steps:
-      - name: Install jq
-        shell: bash -l {0}
-        run: |
-          sudo apt-get install jq
-
       - name: Checkout repo
         uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
@@ -46,16 +41,11 @@ jobs:
           python -c "import sys; print(sys.executable)"
           which python
 
-      - name: Build conda package
+      - name: Build with pip
         run: |
-          pip install --no-cache-dir scikit-build cmake ninja cython
+          pip install --no-cache-dir meson-python ninja cmake cython
           pip install --no-cache-dir numpy ${{ matrix.use_pre }}
-          echo "CONDA_PREFFIX is '${CONDA_PREFIX}'"
-          export MKLROOT=${CONDA_PREFIX}
-          CC=icx pip install . --no-build-isolation --no-deps --verbose
+          CC=icx pip install -e . --no-build-isolation --no-deps --verbose
           pip install --no-cache-dir pytest
           pip list
-          # mkl_umath cannot be installed in editable mode, we need
-          # to change directory before importing it and running tests
-          cd ..
-          python -m pytest -v --pyargs mkl_umath
+          python -m pytest -sv --pyargs mkl_umath

.github/workflows/conda-package-cf.yml

@@ -3,7 +3,7 @@ name: Conda package with conda-forge channel only
 on:
     push:
       branches:
-        - master
+        - main
     pull_request:
 
 permissions: read-all

.github/workflows/conda-package.yml

@@ -3,7 +3,7 @@ name: Conda package
 on:
     push:
       branches:
-        - master
+        - main
     pull_request:
 
 permissions: read-all
@@ -75,12 +75,16 @@ jobs:
         run: |
           conda list -n base
 
+      - name: Store conda paths as envs
+        run: |
+          echo "CONDA_BLD=${CONDA}/conda-bld/linux-64" >> "$GITHUB_ENV"
+          echo "WHEELS_OUTPUT_FOLDER=$GITHUB_WORKSPACE/" >> "$GITHUB_ENV"
+
       - name: Build conda package
         run: |
           CHANNELS=(-c "https://software.repos.intel.com/python/conda" -c "conda-forge" --override-channels)
           VERSIONS=(--python "${{ matrix.python }}" --numpy "${{ matrix.numpy }}")
           TEST=(--no-test)
-          echo "CONDA_BLD=${CONDA}/conda-bld/linux-64" >> "$GITHUB_ENV"
 
           conda build \
             "${TEST[@]}" \
@@ -94,6 +98,12 @@ jobs:
           name: ${{ env.PACKAGE_NAME }} ${{ runner.os }} Python ${{ matrix.python }}
           path: ${{ env.CONDA_BLD }}/${{ env.PACKAGE_NAME }}-*.conda
 
+      - name: Upload wheels artifact
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: ${{ env.PACKAGE_NAME }} ${{ runner.os }} Wheels Python ${{ matrix.python }}
+          path: ${{ env.WHEELS_OUTPUT_FOLDER }}${{ env.PACKAGE_NAME }}-*.whl
+
   test_linux:
     needs: build_linux
     runs-on:  ${{ matrix.runner }}
@@ -234,6 +244,7 @@ jobs:
         shell: bash -l {0}
         run: |
           echo "CONDA_BLD=$CONDA/conda-bld/win-64/" | tr "\\\\" '/' >> "$GITHUB_ENV"
+          echo "WHEELS_OUTPUT_FOLDER=$GITHUB_WORKSPACE\\" >> "$GITHUB_ENV"
 
       - name: Install conda build
         run: |
@@ -252,6 +263,12 @@ jobs:
           name: ${{ env.PACKAGE_NAME }} ${{ runner.os }} Python ${{ matrix.python }}
           path: ${{ env.CONDA_BLD }}${{ env.PACKAGE_NAME }}-*.conda
 
+      - name: Upload wheels artifact
+        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
+        with:
+          name: ${{ env.PACKAGE_NAME }} ${{ runner.os }} Wheels Python ${{ matrix.python }}
+          path: ${{ env.WHEELS_OUTPUT_FOLDER }}${{ env.PACKAGE_NAME }}-*.whl
+
   test_windows:
     needs: build_windows
     runs-on:  ${{ matrix.runner }}

.github/workflows/openssf-scorecard.yml

@@ -13,7 +13,7 @@ on:
     - cron: '28 2 * * 1'
     - cron: '28 2 * * 4'
   push:
-    branches: [ "master" ]
+    branches: [ "main" ]
   workflow_dispatch:
 
 

.pre-commit-config.yaml

@@ -103,7 +103,7 @@ repos:
         "-rn", # Only display messages
         "-sn", # Don't display the score
         "--errors-only",
-        "--disable=import-error",
+        "--disable=import-error,no-name-in-module",
         ]
 
 - repo: https://github.com/jumanjihouse/pre-commit-hooks

AGENTS.md

@@ -15,30 +15,39 @@ It provides:
 - **Core C implementation:** `mkl_umath/src/` (ufuncsmodule.c, mkl_umath_loops.c.src)
 - **Cython patch layer:** `mkl_umath/src/_patch_numpy.pyx`
 - **Code generation:** `generate_umath.py`, `generate_umath_doc.py`
-- **Build system:** CMake (CMakeLists.txt) + scikit-build
+- **Build system:** meson-python + Cython
 
 ## Build dependencies
 **Required:**
 - Compiler toolchain: Intel `icx` or `clang` (with Intel-only flags gated when using clang)
-- Intel® OneMKL (mkl-devel)
-- NumPy, Cython, scikit-build, cmake, ninja
+- Intel® oneMKL (`mkl-devel`)
+- meson-python, CMake, Ninja, Cython, NumPy
 
-**Conda environment:**
+**Build against an existing `mkl` installation:**
+
+Install the build dependencies via Conda:
 ```bash
 conda install -c https://software.repos.intel.com/python/conda \
-  mkl-devel dpcpp_linux-64 numpy-base \
-  cmake ninja cython scikit-build
-export MKLROOT=$CONDA_PREFIX
-CC=${CC:-icx} pip install --no-build-isolation --no-deps .  # clang is also supported in CI
+  mkl-devel dpcpp_linux-64 cython meson-python cmake ninja numpy
+```
+or via pip:
+```bash
+pip install mkl-devel cython meson-python cmake ninja numpy
+```
+then build:
+```bash
+CC=icx pip install --no-deps --no-build-isolation .  # clang is also supported in CI
 ```
 
 ## CI/CD
 - **Platforms:** Linux, Windows
 - **Python versions:** 3.10, 3.11, 3.12, 3.13, 3.14
 - **Workflows:** `.github/workflows/`
-  - `conda-package.yml` — main build/test pipeline
-  - `build_pip.yaml` — PyPI wheel builds
-  - `build-with-clang.yml` — Clang compatibility check
+  - `conda-package.yml` — main conda build/test pipeline
+  - `conda-package-cf.yml` — conda-forge-oriented build/test pipeline
+  - `build_pip.yml` — validates pip build with pre-release NumPy
+  - `build-with-clang.yml` — Intel clang compatibility check
+  - `build-with-standard-clang.yml` — standard clang compatibility check
   - `openssf-scorecard.yml` — security scorecard
 
 ## Distribution
@@ -58,13 +67,14 @@ mkl_umath.restore_numpy_umath()  # Restore original NumPy loops
 - **Performance:** Changes should maintain or improve MKL VM utilization
 - **Compatibility:** Must work with upstream NumPy APIs (NEP-36 compliance)
 - **Testing:** Add tests to `mkl_umath/tests/test_basic.py`
-- **Build hygiene:** CMake changes → verify Linux + Windows
+- **Build hygiene:** `meson.build` is the source of truth for build config — verify Linux + Windows
 - **Docs:** Update docstrings via `ufunc_docstrings_numpy{1,2}.py`
 
 ## Code structure
 - **Generated code:** `*.src` files are templates (conv_template.py processes them)
 - **Precision flags:** fp:precise, fimf-precision=high, fprotect-parens (non-negotiable)
-- **Security:** Stack protection, FORTIFY_SOURCE, NX/DEP enforced in CMake
+- **Security:** Stack protection, FORTIFY_SOURCE, NX/DEP enforced in `meson.build`
+- **Build options:** `opt_report` and `mkl_threading` are exposed via `meson.options`
 
 
 ## Common pitfalls
@@ -74,12 +84,11 @@ mkl_umath.restore_numpy_umath()  # Restore original NumPy loops
 - **Compiler/toolchain:** `icx` and `clang` are both supported; when using clang, keep Intel-only flags behind compiler guards.
 - **Build validation:**
   - After setup: `which ${CC:-icx}` → should resolve to the intended compiler toolchain
-  - Verify: `echo $MKLROOT` → should be set
-  - Check: `python -c "import numpy; print(numpy.__version__)"` → confirm Intel NumPy
+  - Check: `python -c "import numpy; print(numpy.__version__)"` → confirm NumPy is available
 
 ## Notes
 - `_vendored/` contains vendored NumPy code generation utilities
-- Version in `mkl_umath/_version.py` (dynamic via setuptools)
+- Version in `mkl_umath/_version.py` (read dynamically by `meson.build`)
 - Patching is runtime-only; no NumPy source modification
 
 ## Directory map

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 * Removed `numpy-base` dependency and `USE_NUMPY_BASE` environment variable from conda recipe [gh-200](https://github.com/IntelPython/mkl_umath/pull/200)
+* Migrated the build system from `scikit-build` to `meson-python`, removing `setup.py` and `CMakeLists.txt` in favor of `meson.build` [gh-166](https://github.com/IntelPython/mkl_umath/pull/166)
+* Renamed the `OPTIMIZATION_REPORT` and `MKL_THREADING` build options to `opt_report` and `mkl_threading`, now passed as meson setup args (e.g. `-Csetup-args=-Dopt_report=true` and `-Csetup-args=-Dmkl_threading=tbb_thread`) [gh-166](https://github.com/IntelPython/mkl_umath/pull/166)
 
 ### Fixed