[smart_holder] snapshot of current PR #3497

.github/workflows/ci.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        runs-on: [ubuntu-latest, windows-latest, macos-latest]
+        runs-on: [ubuntu-latest, windows-2022, macos-latest]
         python:
         - '2.7'
         - '3.5'
@@ -182,6 +182,7 @@ jobs:
     # setuptools
     - name: Setuptools helpers test
       run: pytest tests/extra_setuptools
+      if: "!(matrix.python == '3.5' && matrix.runs-on == 'windows-2022')"
 
 
   deadsnakes:

include/pybind11/detail/common.h

@@ -154,6 +154,14 @@
 // C4505: 'PySlice_GetIndicesEx': unreferenced local function has been removed (PyPy only)
 #  pragma warning(disable: 4505)
 #  if defined(_DEBUG) && !defined(Py_DEBUG)
+// Workaround for a VS 2022 issue.
+// NOTE: This workaround knowingly violates the Python.h include order requirement:
+// https://docs.python.org/3/c-api/intro.html#include-files
+// See https://github.com/pybind/pybind11/pull/3497 for full context.
+#    include <yvals.h>
+#    if _MSVC_STL_VERSION >= 143
+#      include <crtdefs.h>
+#    endif
 #    define PYBIND11_DEBUG_MARKER
 #    undef _DEBUG
 #  endif

include/pybind11/embed.h

@@ -102,6 +102,13 @@ inline wchar_t *widen_chars(const char *safe_arg) {
     wchar_t *widened_arg = Py_DecodeLocale(safe_arg, nullptr);
 #else
     wchar_t *widened_arg = nullptr;
+
+// warning C4996: 'mbstowcs': This function or variable may be unsafe.
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable:4996)
+#endif
+
 #    if defined(HAVE_BROKEN_MBSTOWCS) && HAVE_BROKEN_MBSTOWCS
     size_t count = strlen(safe_arg);
 #    else
@@ -111,6 +118,11 @@ inline wchar_t *widen_chars(const char *safe_arg) {
         widened_arg = new wchar_t[count + 1];
         mbstowcs(widened_arg, safe_arg, count + 1);
     }
+
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
+
 #endif
     return widened_arg;
 }