ci: wire up Visual Studio build with Meson

Add a new job to GitHub Actions and GitLab CI that builds and tests
Meson-based builds with Visual Studio.

A couple notes:

  - While the build job is mandatory, the test job is marked as "manual"
    on GitLab so that it doesn't run by default. We already have a bunch
    of Windows-based jobs, and the computational overhead that these
    cause is simply out of proportion to run the test suite twice.

    The same isn't true for GitHub as I could not find a way to make a
    subset of jobs manually triggered.

  - We disable Perl. This is because we pick up Perl from Git for
    Windows, which outputs different paths ("/c/" instead of "C:\") than
    what we expect in our tests.

  - We don't use the Git for Windows SDK. Instead, the build only
    depends on Visual Studio, Meson and Git for Windows. All the other
    dependencies like curl, pcre2 and zlib get pulled in and compiled
    automatically by Meson and thus do not have to be provided by the
    system.

  - We open-code "ci/run-test-slice.sh". This is because we only have
    direct access to PowerShell, so we manually implement the logic.
    There is an upstream pull request for the Meson build system [1] to
    implement test slicing in Meson directly.

  - We don't process test artifacts for failed CI jobs. This is done to
    keep down prerequisites to a minimum.

All tests are passing.

[1]: https://github.com/mesonbuild/meson/pull/14092

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 90 insertions, 0 deletions

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 900be9957a..7f55f8b3a9 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -248,6 +248,58 @@ jobs:
       with:
         name: failed-tests-windows-vs-${{ matrix.nr }}
         path: ${{env.FAILED_TEST_ARTIFACTS}}
+
+  windows-meson-build:
+    name: win+Meson build
+    needs: ci-config
+    if: needs.ci-config.outputs.enabled == 'yes'
+    runs-on: windows-latest
+    concurrency:
+      group: windows-meson-build-${{ github.ref }}
+      cancel-in-progress: ${{ needs.ci-config.outputs.skip_concurrent == 'yes' }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-python@v5
+    - name: Set up dependencies
+      shell: pwsh
+      run: pip install meson ninja
+    - name: Setup
+      shell: pwsh
+      run: meson setup build -Dperl=disabled
+    - name: Compile
+      shell: pwsh
+      run: meson compile -C build
+    - name: Upload build artifacts
+      uses: actions/upload-artifact@v4
+      with:
+        name: windows-meson-artifacts
+        path: build
+  windows-meson-test:
+    name: win+Meson test
+    runs-on: windows-latest
+    needs: [ci-config, windows-meson-build]
+    strategy:
+      fail-fast: false
+      matrix:
+        nr: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+    concurrency:
+      group: windows-meson-test-${{ matrix.nr }}-${{ github.ref }}
+      cancel-in-progress: ${{ needs.ci-config.outputs.skip_concurrent == 'yes' }}
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-python@v5
+    - name: Set up dependencies
+      shell: pwsh
+      run: pip install meson ninja
+    - name: Download build artifacts
+      uses: actions/download-artifact@v4
+      with:
+        name: windows-meson-artifacts
+        path: build
+    - name: Test
+      shell: pwsh
+      run: meson test -C build --list | Select-Object -Skip 1 | Select-String .* | Group-Object -Property { $_.LineNumber % 10 } | Where-Object Name -EQ ${{ matrix.nr }} | ForEach-Object { meson test -C build --no-rebuild --print-errorlogs $_.Group }
+
   regular:
     name: ${{matrix.vector.jobname}} (${{matrix.vector.pool}})
     needs: ci-config
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 9254e01583..4976e18a05 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -149,6 +149,44 @@ test:mingw64:
     - git-sdk/usr/bin/bash.exe -l -c 'ci/print-test-failures.sh'
   parallel: 10
 
+.msvc-meson:
+  tags:
+    - saas-windows-medium-amd64
+  before_script:
+    - choco install -y git meson ninja openssl
+    - Import-Module $env:ChocolateyInstall\helpers\chocolateyProfile.psm1
+    - refreshenv
+    # The certificate store for Python on Windows is broken and fails to fetch
+    # certificates, see https://bugs.python.org/issue36011. This seems to
+    # mostly be an issue with how the GitLab image is set up as it is a
+    # non-issue on GitHub Actions. Work around the issue by importing
+    # cetrificates manually.
+    - Invoke-WebRequest https://curl.haxx.se/ca/cacert.pem -OutFile cacert.pem
+    - openssl pkcs12 -export -nokeys -in cacert.pem -out certs.pfx -passout "pass:"
+    - Import-PfxCertificate -CertStoreLocation Cert:\LocalMachine\Root -FilePath certs.pfx
+
+build:msvc-meson:
+  extends: .msvc-meson
+  stage: build
+  script:
+    - meson setup build -Dperl=disabled
+    - meson compile -C build
+  artifacts:
+    paths:
+      - build
+
+test:msvc-meson:
+  extends: .msvc-meson
+  stage: test
+  when: manual
+  timeout: 6h
+  needs:
+    - job: "build:msvc-meson"
+      artifacts: true
+  script:
+    - meson test -C build --list | Select-Object -Skip 1 | Select-String .* | Group-Object -Property { $_.LineNumber % $Env:CI_NODE_TOTAL + 1 } | Where-Object Name -EQ $Env:CI_NODE_INDEX | ForEach-Object { meson test -C build --no-rebuild --print-errorlogs $_.Group }
+  parallel: 10
+
 test:fuzz-smoke-tests:
   image: ubuntu:latest
   stage: test