tmp(ci): probe the three windows images — do NOT merge

.github/workflows/tmp-windows-image-probe.yml

@@ -0,0 +1,174 @@
+# TEMPORARY — delete once the windows image question is settled.
+#
+# mcpplibs/mcpp-index#385 pinned the windows leg to `windows-2022` because
+# `windows-latest` (= windows-2025-vs2026, MSVC STL 14.51) cannot compile
+# `huxerui.huxerui`: clang instantiates MSVC STL's vectorized `std::find` for a
+# 24-byte type and hits `static_assert(false, "unexpected size")`
+# (mcpp-community/mcpp#609).
+#
+# The pin worked and cost three members: `vulkan`, `eui-neo-vulkan` and
+# `vulkan-hpp-module` now fail at RUN time with 0xC0000135
+# (STATUS_DLL_NOT_FOUND). The Vulkan loader is not a Windows component -- it
+# arrives with a GPU driver or the SDK -- so whether an image carries
+# `vulkan-1.dll` is a property of the image, and 2022 apparently does not.
+#
+# `windows-2025` was never tried. If its STL is old enough to compile huxerui
+# and its image new enough to carry the loader, it settles both.
+#
+# This workflow answers that in one run instead of a 50-minute full matrix. It
+# is a separate FILE on purpose: validate.yml's `paths:` names only itself, so
+# adding this triggers no member selection.
+name: tmp-windows-image-probe
+
+on:
+  workflow_dispatch:
+  pull_request:
+    paths: [".github/workflows/tmp-windows-image-probe.yml"]
+
+env:
+  MCPP_VERSION: "2026.9.11.2"
+
+jobs:
+  probe:
+    strategy:
+      fail-fast: false
+      matrix:
+        image: [windows-2022, windows-2025, windows-latest]
+    runs-on: ${{ matrix.image }}
+    name: probe (${{ matrix.image }})
+    steps:
+      - uses: actions/checkout@v4
+
+      # The whole question, asked directly, before any build can muddy it.
+      - name: What is on this image
+        shell: pwsh
+        run: |
+          Write-Host "label        : ${{ matrix.image }}"
+          Write-Host "ImageOS      : $env:ImageOS"
+          Write-Host "ImageVersion : $env:ImageVersion"
+          Write-Host ""
+          Write-Host "--- Vulkan loader (the vulkan members' failure) ---"
+          foreach ($p in @("$env:SystemRoot\System32\vulkan-1.dll",
+                           "$env:SystemRoot\SysWOW64\vulkan-1.dll")) {
+            if (Test-Path $p) {
+              $v = (Get-Item $p).VersionInfo.FileVersion
+              Write-Host "  PRESENT  $p  ($v)"
+            } else {
+              Write-Host "  absent   $p"
+            }
+          }
+          Write-Host ""
+          Write-Host "--- MSVC toolsets (huxerui's failure) ---"
+          Get-ChildItem "C:\Program Files*\Microsoft Visual Studio\*\*\VC\Tools\MSVC\*" -Directory -EA SilentlyContinue |
+            ForEach-Object { Write-Host "  $($_.FullName)" }
+
+      - name: Download mcpp
+        shell: bash
+        env:
+          MCPP_ARCHIVE: mcpp-${{ env.MCPP_VERSION }}-windows-x86_64.zip
+          MCPP_ROOT: mcpp-${{ env.MCPP_VERSION }}-windows-x86_64
+        run: |
+          curl -L -fsS -o "$MCPP_ARCHIVE" \
+            "https://github.com/mcpp-community/mcpp/releases/download/v${MCPP_VERSION}/${MCPP_ARCHIVE}"
+          powershell -NoProfile -Command "Expand-Archive -Force -Path '${MCPP_ARCHIVE}' -DestinationPath '.'"
+          root="$PWD/$MCPP_ROOT"
+          mkdir -p "$HOME/.mcpp/registry"
+          cp -a "$root/registry/." "$HOME/.mcpp/registry/"
+          echo "MCPP_HOME=$HOME/.mcpp" >> "$GITHUB_ENV"
+          echo "MCPP=$(cygpath -m "$root/bin/mcpp.exe")" >> "$GITHUB_ENV"
+
+      # Both members, both allowed to fail, so every image reports a full row
+      # rather than stopping at the first red.
+      - name: huxerui-module (the compile question)
+        id: hux
+        continue-on-error: true
+        shell: bash
+        env:
+          MCPP_INDEX_MIRROR: GLOBAL
+        run: |
+          "$MCPP" test -p huxerui-module
+
+      - name: vulkan (the loader question)
+        id: vk
+        continue-on-error: true
+        shell: bash
+        env:
+          MCPP_INDEX_MIRROR: GLOBAL
+        run: |
+          "$MCPP" test -p vulkan
+
+      - name: Row
+        shell: bash
+        run: |
+          echo "=============================================="
+          echo " image           ${{ matrix.image }}"
+          echo " huxerui-module  ${{ steps.hux.outcome }}"
+          echo " vulkan          ${{ steps.vk.outcome }}"
+          echo "=============================================="
+
+  # THE IMAGE IS NOT THE ONLY AXIS, and the inventory step is what showed it:
+  # windows-2025 carries 14.29.30133, 14.44.35207 AND 14.51.36231. clang picks
+  # the newest and dies in it. If it can be pointed at 14.44 instead, the trade
+  # disappears -- a new image (loader present, vulkan passes) with an old STL
+  # (no vectorized-find assert, huxerui compiles).
+  #
+  # Two ways to ask clang, probed separately because they fail differently:
+  # the environment a developer prompt exports (`VCToolsInstallDir`), and
+  # clang's own `/vctoolsdir`. If neither reaches it, the toolset selection is
+  # mcpp's to make and this stops being fixable from CI.
+  toolset:
+    strategy:
+      fail-fast: false
+      matrix:
+        how: [vctoolsinstalldir, vctoolsdir-flag]
+    runs-on: windows-2025
+    name: toolset 14.44 via ${{ matrix.how }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Point at 14.44
+        shell: pwsh
+        run: |
+          $root = "C:\Program Files\Microsoft Visual Studio\18\Enterprise\VC\Tools\MSVC\14.44.35207"
+          if (-not (Test-Path $root)) { throw "14.44 not on this image" }
+          Write-Host "using $root"
+          if ("${{ matrix.how }}" -eq "vctoolsinstalldir") {
+            "VCToolsInstallDir=$root\" | Out-File -Append -Encoding utf8 $env:GITHUB_ENV
+          } else {
+            "MCPP_EXTRA_CXXFLAGS=/vctoolsdir `"$root`"" | Out-File -Append -Encoding utf8 $env:GITHUB_ENV
+          }
+
+      - name: Download mcpp
+        shell: bash
+        env:
+          MCPP_ARCHIVE: mcpp-${{ env.MCPP_VERSION }}-windows-x86_64.zip
+          MCPP_ROOT: mcpp-${{ env.MCPP_VERSION }}-windows-x86_64
+        run: |
+          curl -L -fsS -o "$MCPP_ARCHIVE" \
+            "https://github.com/mcpp-community/mcpp/releases/download/v${MCPP_VERSION}/${MCPP_ARCHIVE}"
+          powershell -NoProfile -Command "Expand-Archive -Force -Path '${MCPP_ARCHIVE}' -DestinationPath '.'"
+          root="$PWD/$MCPP_ROOT"
+          mkdir -p "$HOME/.mcpp/registry"
+          cp -a "$root/registry/." "$HOME/.mcpp/registry/"
+          echo "MCPP_HOME=$HOME/.mcpp" >> "$GITHUB_ENV"
+          echo "MCPP=$(cygpath -m "$root/bin/mcpp.exe")" >> "$GITHUB_ENV"
+
+      - name: huxerui-module
+        id: hux
+        continue-on-error: true
+        shell: bash
+        env:
+          MCPP_INDEX_MIRROR: GLOBAL
+        run: |
+          "$MCPP" test -p huxerui-module
+
+      # Which STL the compile actually reached, whatever the outcome -- a pass
+      # for the wrong reason and a pass for the right one look identical here
+      # otherwise.
+      - name: Which STL did it use
+        if: always()
+        shell: bash
+        run: |
+          echo "how            ${{ matrix.how }}"
+          echo "huxerui-module ${{ steps.hux.outcome }}"
+          grep -rhoE "MSVC\\\\1[0-9]\\.[0-9]+\\.[0-9]+" tests/examples/huxerui-module/target 2>/dev/null | sort -u | head -3 || true