From b938db7cfc42e105e3ff711ffbbb8d51406e1e29 Mon Sep 17 00:00:00 2001
From: Paul Timmins <paul@iqmo.com>
Date: Fri, 19 Sep 2025 21:30:25 +0000
Subject: [PATCH] ci: Enable Ninja builds, which requires msvc vars (via
 msvc-dev-cmd action), disable unnecessary ccache from Windows CIBW

---
 .github/workflows/packaging_wheels.yml | 16 ++++++++++++++--
 pyproject.toml                         | 10 +++++++++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/packaging_wheels.yml b/.github/workflows/packaging_wheels.yml
index ea13b674..d600ca75 100644
--- a/.github/workflows/packaging_wheels.yml
+++ b/.github/workflows/packaging_wheels.yml
@@ -89,14 +89,26 @@ jobs:
           cache-suffix: -${{ matrix.python }}-${{ matrix.platform.cibw_system }}_${{ matrix.platform.arch }}
           python-version: ${{ matrix.python }}
 
+      # Load MSVC environment, needed for Windows - ninja builds
+      # Without this, the linking step will fail.
+      # Note: CIBW uses the host environment for windows, rather than an isolated container
+      - uses: ilammy/msvc-dev-cmd@v1
+        if: ${{ matrix.platform.cibw_system == 'win' }}
+        with:
+          arch: ${{ matrix.platform.arch }}
+
       - name: Build${{ inputs.testsuite != 'none' && ' and test ' || ' ' }}wheels
         uses: pypa/cibuildwheel@v3.1
         env:
           CIBW_ARCHS: ${{ matrix.platform.arch == 'amd64' && 'AMD64' || matrix.platform.arch }}
           CIBW_BUILD: ${{ matrix.python }}-${{ matrix.platform.cibw_system }}_${{ matrix.platform.arch }}
-          # PYTHON_GIL=1: Suppresses the RuntimeWarning that the GIL is enabled on free-threaded builds. 
-          # TODO: Remove PYTHON_GIL=1 when free-threaded is supported. 
+          # PYTHON_GIL=1: Suppresses the RuntimeWarning that the GIL is enabled on free-threaded builds.
+          # TODO: Remove PYTHON_GIL=1 when free-threaded is supported.
+          # CMAKE_BUILD_TYPE=Release: Override Debug default when MSVC dev environment is loaded
           CIBW_ENVIRONMENT: PYTHON_GIL=1
+          # For Windows, msvc-dev-cmd sets build to Debug. So, override it back to Release. 
+          # This is a problem because Debug enables Jemalloc, which fails to build on Windows
+          CIBW_ENVIRONMENT_WINDOWS: PYTHON_GIL=1 CMAKE_BUILD_TYPE=Release
       - name: Upload wheel
         uses: actions/upload-artifact@v4
         with:
diff --git a/pyproject.toml b/pyproject.toml
index bcbb24f6..6938fab9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -123,6 +123,13 @@ if.env.COVERAGE = false
 inherit.cmake.define = "append"
 cmake.define.DISABLE_UNITY = "1"
 
+[[tool.scikit-build.overrides]]
+if.platform-system = "^win32"
+cmake.args = [
+   "-G", "Ninja",
+   "--log-level=DEBUG",
+]
+
 [tool.scikit-build.sdist]
 include = [
     "README.md",
@@ -388,4 +395,5 @@ before-build = ["yum install -y ccache"]
 before-build = ["brew install ccache"]
 
 [tool.cibuildwheel.windows]
-before-build = ["choco install ccache"]
+# Strawberry ccache is already installed on the cibuildwheel images
+before-build = []