task: coverity scanning

.github/workflows/coverity.yml

@@ -0,0 +1,106 @@
+name: Coverity Scan
+
+# Public static analysis via the free Coverity Scan service (scan.coverity.com,
+# operated by Black Duck). Coverity is a compiled-language analyzer: it must wrap
+# the real C build with `cov-build`, so this workflow installs the Meson build
+# stack, compiles the extension under capture, and uploads the result.
+#
+# One-time setup (done once per project, outside this workflow):
+#   1. Register IntelPython/mkl_fft at https://scan.coverity.com/github
+#      (the project name must match COVERITY_PROJECT below).
+#   2. Add two repository secrets (Settings -> Secrets and variables -> Actions):
+#        COVERITY_SCAN_TOKEN  - the project token from the Project Settings tab
+#        COVERITY_SCAN_EMAIL  - a maintainer email for build notifications
+#
+# Free-tier quota for a project under 100K LOC is 28 builds/week, max 4/day, so
+# this runs on a weekly schedule plus on demand rather than per-push.
+
+on:
+  schedule:
+    - cron: "0 1 * * 1"  # Mondays 01:00 UTC; well under the free build quota
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: coverity-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  COVERITY_PROJECT: IntelPython/mkl_fft
+
+jobs:
+  coverity-scan:
+    # Forks lack the COVERITY_SCAN_* secrets; only run on the canonical repo.
+    if: github.repository == 'IntelPython/mkl_fft'
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          fetch-depth: 0
+
+      - name: Setup Python
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: "3.12"
+          architecture: x64
+
+      # Meson locates MKL through its CMake config (see meson.build), so the
+      # mkl-devel wheel is enough -- no MKLROOT or oneAPI install required.
+      - name: Install mkl_fft dependencies
+        run: pip install meson-python ninja cmake cython "numpy>=2" mkl-devel
+
+      - name: Download Coverity Build Tool
+        env:
+          COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}
+        run: |
+          curl --location --no-progress-meter \
+               --data-urlencode "token=${COVERITY_SCAN_TOKEN}" \
+               --data-urlencode "project=${COVERITY_PROJECT}" \
+               --output cov-analysis.tar.gz \
+               https://scan.coverity.com/download/linux64
+          # An invalid token/project returns a small HTML error page, not the
+          # multi-hundred-MB tarball. Fail loudly with a clear hint if so.
+          if [ "$(stat -c '%s' cov-analysis.tar.gz)" -lt 1000000 ]; then
+            echo "::error::Coverity build tool download failed. Verify the COVERITY_SCAN_TOKEN secret and that the registered project name matches '${COVERITY_PROJECT}'."
+            head -c 512 cov-analysis.tar.gz || true
+            exit 1
+          fi
+          mkdir -p cov-analysis
+          tar -xzf cov-analysis.tar.gz --strip 1 -C cov-analysis
+          echo "${PWD}/cov-analysis/bin" >> "$GITHUB_PATH"
+
+      - name: Configure Coverity for GCC
+        run: cov-configure --gcc
+
+      - name: Build under cov-build
+        run: |
+          # Meson caches its build tree in build/ and skips compiling when it is
+          # up to date, which would leave Coverity with nothing to capture and
+          # get the upload rejected. Remove it to force a real rebuild.
+          rm -rf build
+          cov-build --dir cov-int pip install -e . --no-build-isolation --no-deps 2>&1 | tee cov-build.log
+          # The extension has 2 C translation units (the generated mklfft.c and
+          # the Cython-generated _pydfti.c); bail out if none were captured.
+          if ! grep -qE "Emitted [1-9][0-9]* .*compilation unit" cov-build.log; then
+            echo "::error::Coverity captured 0 compilation units — the C build did not run under cov-build."
+            exit 1
+          fi
+
+      - name: Submit results to Coverity Scan
+        env:
+          COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}
+          COVERITY_SCAN_EMAIL: ${{ secrets.COVERITY_SCAN_EMAIL }}
+        run: |
+          tar -czf cov-int.tgz cov-int
+          curl --no-progress-meter \
+               --form token="${COVERITY_SCAN_TOKEN}" \
+               --form email="${COVERITY_SCAN_EMAIL}" \
+               --form file=@cov-int.tgz \
+               --form version="${GITHUB_SHA}" \
+               --form description="GitHub Actions ${GITHUB_REF_NAME} (run ${GITHUB_RUN_ID})" \
+               --form project="${COVERITY_PROJECT}" \
+               https://scan.coverity.com/builds

README.md

@@ -2,6 +2,7 @@
 [![Editable build using pip and pre-release NumPy](https://github.com/IntelPython/mkl_fft/actions/workflows/build_pip.yml/badge.svg)](https://github.com/IntelPython/mkl_fft/actions/workflows/build_pip.yml)
 [![Conda package with conda-forge channel only](https://github.com/IntelPython/mkl_fft/actions/workflows/conda-package-cf.yml/badge.svg)](https://github.com/IntelPython/mkl_fft/actions/workflows/conda-package-cf.yml)
 [![OpenSSF Scorecard](https://api.securityscorecards.dev/projects/github.com/IntelPython/mkl_fft/badge)](https://securityscorecards.dev/viewer/?uri=github.com/IntelPython/mkl_fft)
+[![Coverity Scan Build Status](https://scan.coverity.com/projects/33202/badge.svg)](https://scan.coverity.com/projects/intelpython-mkl_fft)
 
 ## `mkl_fft` --  a NumPy-based Python interface to Intel® oneAPI Math Kernel Library (oneMKL) Fourier Transform Functions