ci(windows): build volrover3 against the cvcpkg python311 (now published)

.github/workflows/publish-cvcpkg.yml

@@ -418,14 +418,12 @@ jobs:
           # so install it explicitly. (It was dropped when the python packages moved
           # to per-interpreter -cp3XX columns; the SDK closure no longer carries it.)
           #
-          # python311 is published for linux + macos but NOT windows (windows python
-          # packaging is still experimental — see the windows_pycvc input). Request it
-          # only where it exists; windows volrover3 stays blocked at the hermeticity
-          # guard until a windows python3XX is published, which is fine — the whole
-          # build-volrover3 job is continue-on-error.
-          py_dep=()
-          if [ "${{ matrix.platform }}" != "windows" ]; then py_dep=(python311); fi
-          cvcpkg install libcvc vtk cvcgl yaml-cpp "${py_dep[@]}" \
+          # python311 is now published on every platform including windows (the
+          # windows_pycvc binding stack landed 2026-08-19), so install the embedded
+          # interpreter everywhere — the CMakeLists hermeticity guard requires the
+          # app to embed the SAME python3XX the prefix's pycvc/pycvc-gl were built
+          # against, not the runner's system python.
+          cvcpkg install libcvc vtk cvcgl yaml-cpp python311 \
             --prefix "$GITHUB_WORKSPACE/cvc-deps" \
             --platform "${{ matrix.platform }}" \
             --config release \
@@ -454,6 +452,9 @@ jobs:
             -DVOLROVER_RELEASE=ON `
             -DCMAKE_TOOLCHAIN_FILE="$env:VCPKG_INSTALLATION_ROOT/scripts/buildsystems/vcpkg.cmake" `
             -DCMAKE_PREFIX_PATH="${{ github.workspace }}\cvc-deps;$env:Qt6_DIR" `
+            -DPython3_EXECUTABLE="${{ github.workspace }}\cvc-deps\python.exe" `
+            -DPython3_ROOT_DIR="${{ github.workspace }}\cvc-deps" `
+            -DPython3_FIND_STRATEGY=LOCATION `
             -DUSE_QT6=ON `
             -DDISABLE_CGAL=ON `
             -DBUILD_VOLROVER3=ON `

volrover3/CMakeLists.txt

@@ -75,15 +75,27 @@ endif()
 
 find_package(Python3 REQUIRED COMPONENTS Interpreter Development.Embed)
 
-if(_vr3_deps_prefix)
-  file(REAL_PATH "${_vr3_deps_prefix}" _vr3_prefix_real)
+if(CMAKE_PREFIX_PATH)
+  # Accept the interpreter if it resolves under ANY CMAKE_PREFIX_PATH entry, not
+  # just the first. A toolchain can PREPEND its own prefix (vcpkg puts
+  # C:/vcpkg/installed/<triplet> at index 0), so a `list(GET ... 0)` check would
+  # false-fail even when the cvcpkg python is correctly under a later entry. A
+  # system/registry python is under none of them, so this still rejects it.
   file(REAL_PATH "${Python3_EXECUTABLE}" _vr3_python_real)
-  string(FIND "${_vr3_python_real}" "${_vr3_prefix_real}" _vr3_python_in_prefix)
-  if(NOT _vr3_python_in_prefix EQUAL 0)
+  set(_vr3_python_hermetic FALSE)
+  foreach(_vr3_p IN LISTS CMAKE_PREFIX_PATH)
+    file(REAL_PATH "${_vr3_p}" _vr3_p_real)
+    string(FIND "${_vr3_python_real}" "${_vr3_p_real}" _vr3_idx)
+    if(_vr3_idx EQUAL 0)
+      set(_vr3_python_hermetic TRUE)
+      break()
+    endif()
+  endforeach()
+  if(NOT _vr3_python_hermetic)
     message(FATAL_ERROR
-      "volrover3: embedded Python escaped the dependency prefix.\n"
-      "  found:  ${Python3_EXECUTABLE}\n"
-      "  prefix: ${_vr3_deps_prefix}\n"
+      "volrover3: embedded Python escaped the dependency prefix(es).\n"
+      "  found:    ${Python3_EXECUTABLE}\n"
+      "  prefixes: ${CMAKE_PREFIX_PATH}\n"
       "Linking a system interpreter breaks hermeticity: the app would embed a "
       "different python3XX.dll than the prefix's pycvc/pycvc-gl were built "
       "against. Install the python3XX cvcpkg package into the prefix.")