[python3] Add feature deprecated-win7-support. (#16420)

* [python3] Move /MACHINE into MSBuild file.

This prevents potential patch application conflicts.

* [python3] Add feature deprecated-win7-support.

This backports the fix for bpo-39401 from the Python 3.8 branch instead
of the one from the Python 3.9 branch, which dropped support for Windows
7.

* [python3] Bump port version.

* [python3] Fix goof in static patch that omitted pathcch.lib.

* x-add-version

* [python3] Revert trivial patch changes

Co-authored-by: Robert Schumacher <roschuma@microsoft.com>

5 files changed, 159 insertions, 29 deletions

diff --git a/ports/python3/0001-static-library.patch b/ports/python3/0001-static-library.patch
index f7d46d094..93a89a2e3 100644
--- a/ports/python3/0001-static-library.patch
+++ b/ports/python3/0001-static-library.patch
@@ -1,19 +1,19 @@
-From 4bd06273a9ed63f17966f113dc61a6051bad8b86 Mon Sep 17 00:00:00 2001
+From 14d91e4f4a9377f47cc4cc33faeeb7c82f64b176 Mon Sep 17 00:00:00 2001
 From: Adam Johnson <AdamJohnso@gmail.com>
 Date: Thu, 28 May 2020 17:25:21 -0400
-Subject: [PATCH 1/6] static library
+Subject: [PATCH 1/7] static library
 
 builds the pythoncore as a static library instead of a DLL
 ---
- PC/pyconfig.h              |  7 +++++++
- PCbuild/pythoncore.vcxproj | 16 ++++++++++++++--
- 2 files changed, 21 insertions(+), 2 deletions(-)
+ PC/pyconfig.h              | 9 +++++++++
+ PCbuild/pythoncore.vcxproj | 4 ++--
+ 2 files changed, 11 insertions(+), 2 deletions(-)
 
 diff --git a/PC/pyconfig.h b/PC/pyconfig.h
-index 02216b5068..7e0ba881a5 100644
+index d7d3cf081e..34269f0b75 100644
 --- a/PC/pyconfig.h
 +++ b/PC/pyconfig.h
-@@ -252,6 +252,7 @@ typedef int pid_t;
+@@ -251,6 +251,7 @@ typedef int pid_t;
  
  /* For Windows the Python core is in a DLL by default.  Test
  Py_NO_ENABLE_SHARED to find out.  Also support MS_NO_COREDLL for b/w compat */
@@ -21,7 +21,7 @@ index 02216b5068..7e0ba881a5 100644
  #if !defined(MS_NO_COREDLL) && !defined(Py_NO_ENABLE_SHARED)
  #       define Py_ENABLE_SHARED 1 /* standard symbol for shared library */
  #       define MS_COREDLL       /* deprecated old symbol */
-@@ -277,6 +278,12 @@ Py_NO_ENABLE_SHARED to find out.  Also support MS_NO_COREDLL for b/w compat */
+@@ -276,6 +277,14 @@ Py_NO_ENABLE_SHARED to find out.  Also support MS_NO_COREDLL for b/w compat */
  #                       endif /* _DEBUG */
  #               endif /* _MSC_VER */
  #       endif /* Py_BUILD_CORE */
@@ -30,12 +30,14 @@ index 02216b5068..7e0ba881a5 100644
 +#       pragma comment(lib, "version.lib")
 +#       pragma comment(lib, "shlwapi.lib")
 +#       pragma comment(lib, "ws2_32.lib")
-+#       pragma comment(lib, "pathcch.lib")
++#       if Py_WINVER > 0x0601
++#           pragma comment(lib, "pathcch.lib")
++#       endif /* Py_WINVER */
  #endif /* MS_COREDLL */
  
  #if defined(MS_WIN64)
 diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
-index 2625d0293d..dbe236829a 100644
+index 2625d0293d..2f8bdaa931 100644
 --- a/PCbuild/pythoncore.vcxproj
 +++ b/PCbuild/pythoncore.vcxproj
 @@ -73,7 +73,7 @@
@@ -47,7 +49,7 @@ index 2625d0293d..dbe236829a 100644
      <UseOfMfc>false</UseOfMfc>
    </PropertyGroup>
    <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
-@@ -102,12 +102,24 @@
+@@ -102,7 +102,7 @@
        <AdditionalOptions>/Zm200  %(AdditionalOptions)</AdditionalOptions>
        <AdditionalIncludeDirectories>$(PySourcePath)Python;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
        <AdditionalIncludeDirectories Condition="$(IncludeExternals)">$(zlibDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
@@ -56,23 +58,6 @@ index 2625d0293d..dbe236829a 100644
        <PreprocessorDefinitions Condition="$(IncludeExternals)">_Py_HAVE_ZLIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
      </ClCompile>
      <Link>
-       <AdditionalDependencies>version.lib;shlwapi.lib;ws2_32.lib;pathcch.lib;%(AdditionalDependencies)</AdditionalDependencies>
-     </Link>
-+    <Lib>
-+      <TargetMachine Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">MachineX86</TargetMachine>
-+    </Lib>
-+    <Lib>
-+      <TargetMachine Condition="'$(Configuration)|$(Platform)'=='PGInstrument|Win32'">MachineX86</TargetMachine>
-+    </Lib>
-+    <Lib>
-+      <TargetMachine Condition="'$(Configuration)|$(Platform)'=='PGUpdate|Win32'">MachineX86</TargetMachine>
-+    </Lib>
-+    <Lib>
-+      <TargetMachine Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">MachineX86</TargetMachine>
-+    </Lib>
-   </ItemDefinitionGroup>
-   <ItemGroup>
-     <ClInclude Include="..\Include\Python-ast.h" />
 -- 
 2.28.0.windows.1
 
diff --git a/ports/python3/0007-restore-support-for-windows-7.patch b/ports/python3/0007-restore-support-for-windows-7.patch
new file mode 100644
index 000000000..4efb19012
--- /dev/null
+++ b/ports/python3/0007-restore-support-for-windows-7.patch
@@ -0,0 +1,124 @@
+From e30a560527d17ae81685dd11d3268bc982af2048 Mon Sep 17 00:00:00 2001
+From: Adam Johnson <AdamJohnso@gmail.com>
+Date: Tue, 16 Feb 2021 18:03:07 -0500
+Subject: [PATCH 7/7] restore support for windows 7
+
+this backports the windows 7 compatible fix for bpo-39401 from gh-18234,
+originally authored by Steve Dower, and removes explicit dependencies on
+pathcch.
+---
+ PC/getpathp.c              | 55 +++++++++++++++++++++++++++++++++++---
+ PC/pyconfig.h              |  4 +--
+ PCbuild/pythoncore.vcxproj |  2 +-
+ 3 files changed, 54 insertions(+), 7 deletions(-)
+
+diff --git a/PC/getpathp.c b/PC/getpathp.c
+index 53da3a6d05..3d58bbfe70 100644
+--- a/PC/getpathp.c
++++ b/PC/getpathp.c
+@@ -250,14 +250,43 @@ ismodule(wchar_t *filename, int update_filename)
+    stuff as fits will be appended.
+ */
+ 
++
++static int _PathCchCombineEx_Initialized = 0;
++typedef HRESULT(__stdcall *PPathCchCombineEx) (PWSTR pszPathOut, size_t cchPathOut,
++                                               PCWSTR pszPathIn, PCWSTR pszMore,
++                                               unsigned long dwFlags);
++static PPathCchCombineEx _PathCchCombineEx;
++
+ static void
+ join(wchar_t *buffer, const wchar_t *stuff)
+ {
+-    if (FAILED(PathCchCombineEx(buffer, MAXPATHLEN+1, buffer, stuff, 0))) {
+-        Py_FatalError("buffer overflow in getpathp.c's join()");
++    if (_PathCchCombineEx_Initialized == 0) {
++        HMODULE pathapi = LoadLibraryExW(L"api-ms-win-core-path-l1-1-0.dll", NULL,
++                                         LOAD_LIBRARY_SEARCH_SYSTEM32);
++        if (pathapi) {
++            _PathCchCombineEx = (PPathCchCombineEx)GetProcAddress(pathapi, "PathCchCombineEx");
++        }
++        else {
++            _PathCchCombineEx = NULL;
++        }
++        _PathCchCombineEx_Initialized = 1;
++    }
++    if (_PathCchCombineEx) {
++        if (FAILED(_PathCchCombineEx(buffer, MAXPATHLEN+1, buffer, stuff, 0))) {
++            Py_FatalError("buffer overflow in getpathp.c's join()");
++        }
++    } else {
++        if (!PathCombineW(buffer, buffer, stuff)) {
++            Py_FatalError("buffer overflow in getpathp.c's join()");
++        }
+     }
+ }
+ 
++static int _PathCchCanonicalizeEx_Initialized = 0;
++typedef HRESULT(__stdcall *PPathCchCanonicalizeEx) (PWSTR pszPathOut, size_t cchPathOut,
++    PCWSTR pszPathIn, unsigned long dwFlags);
++static PPathCchCanonicalizeEx _PathCchCanonicalizeEx;
++
+ /* Call PathCchCanonicalizeEx(path): remove navigation elements such as "."
+    and ".." to produce a direct, well-formed path. */
+ static PyStatus
+@@ -267,8 +296,26 @@ canonicalize(wchar_t *buffer, const wchar_t *path)
+         return _PyStatus_NO_MEMORY();
+     }
+ 
+-    if (FAILED(PathCchCanonicalizeEx(buffer, MAXPATHLEN + 1, path, 0))) {
+-        return INIT_ERR_BUFFER_OVERFLOW();
++    if (_PathCchCanonicalizeEx_Initialized == 0) {
++        HMODULE pathapi = LoadLibraryExW(L"api-ms-win-core-path-l1-1-0.dll", NULL,
++                                         LOAD_LIBRARY_SEARCH_SYSTEM32);
++        if (pathapi) {
++            _PathCchCanonicalizeEx = (PPathCchCanonicalizeEx)GetProcAddress(pathapi, "PathCchCanonicalizeEx");
++        }
++        else {
++            _PathCchCanonicalizeEx = NULL;
++        }
++        _PathCchCanonicalizeEx_Initialized = 1;
++    }
++    if (_PathCchCanonicalizeEx) {
++        if (FAILED(_PathCchCanonicalizeEx(buffer, MAXPATHLEN + 1, path, 0))) {
++            return INIT_ERR_BUFFER_OVERFLOW();
++        }
++    }
++    else {
++        if (!PathCanonicalizeW(buffer, path)) {
++            return INIT_ERR_BUFFER_OVERFLOW();
++        }
+     }
+     return _PyStatus_OK();
+ }
+diff --git a/PC/pyconfig.h b/PC/pyconfig.h
+index 34269f0b75..812f6d9353 100644
+--- a/PC/pyconfig.h
++++ b/PC/pyconfig.h
+@@ -136,8 +136,8 @@ WIN32 is still required for the locale module.
+ 
+ /* set the version macros for the windows headers */
+ /* Python 3.9+ requires Windows 8 or greater */
+-#define Py_WINVER 0x0602 /* _WIN32_WINNT_WIN8 */
+-#define Py_NTDDI NTDDI_WIN8
++#define Py_WINVER 0x0601 /* _WIN32_WINNT_WIN7 */
++#define Py_NTDDI NTDDI_WIN7
+ 
+ /* We only set these values when building Python - we don't want to force
+    these values on extensions, as that will affect the prototypes and
+diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
+index d8e8d2d086..df2892b0de 100644
+--- a/PCbuild/pythoncore.vcxproj
++++ b/PCbuild/pythoncore.vcxproj
+@@ -106,7 +106,7 @@
+       <PreprocessorDefinitions Condition="$(IncludeExternals)">_Py_HAVE_ZLIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+     </ClCompile>
+     <Link>
+-      <AdditionalDependencies>version.lib;shlwapi.lib;ws2_32.lib;pathcch.lib;%(AdditionalDependencies)</AdditionalDependencies>
++      <AdditionalDependencies>version.lib;shlwapi.lib;ws2_32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+     </Link>
+   </ItemDefinitionGroup>
+   <ItemGroup>
+-- 
+2.28.0.windows.1
+
diff --git a/ports/python3/portfile.cmake b/ports/python3/portfile.cmake
index ee19476cf..3a90a7913 100644
--- a/ports/python3/portfile.cmake
+++ b/ports/python3/portfile.cmake
@@ -19,6 +19,15 @@ if(VCPKG_LIBRARY_LINKAGE STREQUAL "static")
     list(PREPEND PATCHES 0001-static-library.patch)
 endif()
 
+# Python 3.9 removed support for Windows 7. This patch re-adds support for Windows 7 and is therefore
+# required to build this port on Windows 7 itself due to Python using itself in its own build system.
+if("deprecated-win7-support" IN_LIST FEATURES)
+    list(APPEND PATCHES 0007-restore-support-for-windows-7.patch)
+    message(WARNING "Windows 7 support is deprecated and may be removed at any time.")
+elseif(VCPKG_TARGET_IS_WINDOWS AND CMAKE_SYSTEM_VERSION EQUAL 6.1)
+    message(FATAL_ERROR "python3 requires the feature deprecated-win7-support when building on Windows 7.")
+endif()
+
 vcpkg_from_github(
     OUT_SOURCE_PATH SOURCE_PATH
     REPO python/cpython
diff --git a/ports/python3/python_vcpkg.props.in b/ports/python3/python_vcpkg.props.in
index c786e5fa0..e5b6093a5 100644
--- a/ports/python3/python_vcpkg.props.in
+++ b/ports/python3/python_vcpkg.props.in
@@ -31,5 +31,11 @@
         ${BZ2_DEBUG};${EXPAT_DEBUG};${FFI_DEBUG};${LZMA_DEBUG};${SQLITE_DEBUG};%(AdditionalDependencies)

       </AdditionalDependencies>

     </Link>

+

+    <Lib>

+      <!-- Required to prevent linker errors on Visual Studio 2017 with static CRT -->

+      <TargetMachine Condition="'${VCPKG_TARGET_ARCHITECTURE}'=='x86'">MachineX86</TargetMachine>

+      <TargetMachine Condition="'${VCPKG_TARGET_ARCHITECTURE}'=='x64'">MachineX64</TargetMachine>

+    </Lib>

   </ItemDefinitionGroup>

 </Project>

diff --git a/ports/python3/vcpkg.json b/ports/python3/vcpkg.json
index 0a0b7778f..f997398f8 100644
--- a/ports/python3/vcpkg.json
+++ b/ports/python3/vcpkg.json
@@ -1,6 +1,7 @@
 {
   "name": "python3",
   "version-string": "3.9.2",
+  "port-version": 1,
   "description": "The Python programming language",
   "homepage": "https://github.com/python/cpython",
   "supports": "!(arm | uwp)",
@@ -35,5 +36,10 @@
       "platform": "!(windows & static)"
     },
     "zlib"
-  ]
+  ],
+  "features": {
+    "deprecated-win7-support": {
+      "description": "Deprecated support for the Windows 7 platform -- may be removed at any time."
+    }
+  }
 }