Fix conda build for Windows (pytorch#19824)

Summary:
Let's test it before merging.
Pull Request resolved: pytorch#19824

Differential Revision: D15116111

Pulled By: soumith

fbshipit-source-id: 0a73de3f045ee1349061674f5f8e2aaba382493c

Author: peterjc123

cmake/Dependencies.cmake

@@ -338,6 +338,22 @@ if(BUILD_TEST)
   if (NOT CAFFE2_USE_MSVC_STATIC_RUNTIME)
       set(gtest_force_shared_crt ON CACHE BOOL "force shared crt on gtest" FORCE)
   endif()
+  # We need to replace googletest cmake scripts too.
+  # Otherwise, it will sometimes break the build.
+  # To make the git clean after the build, we make a backup first.
+  if (MSVC AND MSVC_Z7_OVERRIDE)
+    execute_process(
+      COMMAND ${CMAKE_COMMAND}
+              "-DFILENAME=${CMAKE_CURRENT_LIST_DIR}/../third_party/googletest/googletest/cmake/internal_utils.cmake"
+              "-DBACKUP=${CMAKE_CURRENT_LIST_DIR}/../third_party/googletest/googletest/cmake/internal_utils.cmake.bak"
+              "-DREVERT=0"
+              "-P"
+              "${CMAKE_CURRENT_LIST_DIR}/GoogleTestPatch.cmake"
+      RESULT_VARIABLE _exitcode)
+    if(NOT ${_exitcode} EQUAL 0)
+      message(WARNING "Patching failed for Google Test. The build may fail.")
+    endif()
+  endif()
 
   # Add googletest subdirectory but make sure our INCLUDE_DIRECTORIES
   # don't bleed into it. This is because libraries installed into the root conda
@@ -363,6 +379,21 @@ if(BUILD_TEST)
 
   # Recover build options.
   set(BUILD_SHARED_LIBS ${TEMP_BUILD_SHARED_LIBS} CACHE BOOL "Build shared libs" FORCE)
+
+  # To make the git clean after the build, we revert the changes here.
+  if (MSVC AND MSVC_Z7_OVERRIDE)
+    execute_process(
+      COMMAND ${CMAKE_COMMAND}
+              "-DFILENAME=${CMAKE_CURRENT_LIST_DIR}/../third_party/googletest/googletest/cmake/internal_utils.cmake"
+              "-DBACKUP=${CMAKE_CURRENT_LIST_DIR}/../third_party/googletest/googletest/cmake/internal_utils.cmake.bak"
+              "-DREVERT=1"
+              "-P"
+              "${CMAKE_CURRENT_LIST_DIR}/GoogleTestPatch.cmake"
+      RESULT_VARIABLE _exitcode)
+    if(NOT ${_exitcode} EQUAL 0)
+      message(WARNING "Reverting changes failed for Google Test. The build may fail.")
+    endif()
+  endif()
 endif()
 
 # ---[ FBGEMM

cmake/GoogleTestPatch.cmake

@@ -0,0 +1,24 @@
+# CMake file to replace the string contents in Google Test and Google Mock
+# Usage example:
+# Patch the cmake file
+#   cmake -DFILENAME=internal_utils.cmake
+#         -DBACKUP=internal_utils.cmake.bak
+#         -DREVERT=0 
+#         -P GoogleTestPatch.cmake 
+# Revert the changes
+#   cmake -DFILENAME=internal_utils.cmake
+#         -DBACKUP=internal_utils.cmake.bak
+#         -DREVERT=1 
+#         -P GoogleTestPatch.cmake 
+
+
+if(REVERT)
+  file(READ ${BACKUP} content)
+  file(WRITE ${FILENAME} "${content}")
+  file(REMOVE ${BACKUP})
+else(REVERT)
+  file(READ ${FILENAME} content)
+  file(WRITE ${BACKUP} "${content}")
+  string(REGEX REPLACE "[-/]Z[iI]" "/Z7" content "${content}")
+  file(WRITE ${FILENAME} "${content}")
+endif(REVERT)